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Description: Whether you’re an agriculturalist, a professional meteorologist or a weather hobbyist, building your own weather station can be a really rewarding project. When you’re measuring weather, however, you need some pretty specialized sensors. This kit represents the three core components of weather measurement: wind speed, wind direction and rainfall.

None of the sensors in this kit contain active electronics, instead they use sealed magnetic reed switches and magnets so you’ll need to source a voltage to take any measurements. The positive side of this is that the sensors are easy to interpret:

The rain gauge is a self-emptying bucket-type rain gauge which activates a momentary button closure for each 0.011" of rain that are collected. The anemometer (wind speed meter) encodes the wind speed by simply closing a switch which each rotation. A wind speed of 1.492 MPH produces a switch closure once per second. Finally, the wind vane reports wind direction as a voltage which is produced by the combination of resistors inside the sensor. The vane’s magnet may close two switches at once, allowing up to 16 different positions to be indicated. For more information on how this works, as well as a table of voltage and resistance values for each position, refer to the manual below.

All of the included sensors are supplied with RJ11 terminated cables, for information on the pin-out of the cable, check out the datasheet.

Dimensions: 28.5" x 8"

Kit Includes:

  • Wind Vane
  • Cup Anemometer
  • Tipping Bucket Rain Gauge
  • Two-Part Mounting Mast
  • Rain Gauge Mounting Arm
  • Wind Meter Mounting Bar
  • 2 x Mounting Clamps
  • 4 x Zip Ties

Note: Some basic assembly is required.


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Customer Comments

  • Hi guys,
    The weird data sheet is my fault. I wrote it and provided it to SparkFun with the expectation that they’d clean it up a bit before distributing it. What you’re seeing is part of a collection of notes I made to myself in Notepad for the design of a weather station around these sensors. I think the table formatting got clobbered by conversion to Word. raweb is exactly right that the table shows ADC readings for a voltage divider with different resistor values. I forgot that was in there when I sent it off, which is why it isn’t explained in the document.
    If there are any technical questions I can answer, let me know.

  • Um….please re-shoot the product photos. White on white makes it impossible to see the product detail!

  • In addition, I have modified Steve’s code for the Wind Direction. I used the 10k resistor as suggested from the datasheet. You’ll see I am outputting a float rather than a string for my needs.
    // Find vane direction.
    void calcWindDir() {
    #define NUMDIRS 16
    float adc[NUMDIRS + 1] = {0.0, 0.365, 0.43, 0.535, 0.76, 1.045, 1.295, 1.69,
    2.115, 2.59, 3.005, 3.255, 3.635, 3.94, 4.33, 4.7, 5.0};
    //float expectedVoltages[NUMDIRS] = {0.32, 0.41, 0.45, 0.62, 0.9, 1.19, 1.4, 1.98
    // 2.25, 2.93, 3.08, 3.43, 3.84, 4.04, 4.62, 4.78}
    //char *strVals[NUMDIRS] = {“ESE”,“ENE”, “E”,“SSE”, “SE”,“SSW”, “S”, “NNE”,
    // “NE”,“WSW”,“SW”,“NNW”,“N”,“WNW”, “W”, “NW”};
    float directions[NUMDIRS] = {112.5, 67.5, 90, 157.5, 135, 202.5, 180, 22.5,
    45, 247.5, 225, 337.5, 0, 292.5, 270, 315};
    //byte dirOffset=0;
    unsigned int val;
    float voltage;
    byte x;
    val = analogRead(PIN_WIND_DIR);
    voltage = (float)val / 1024.0 * 5.0;
    for (x=0; x= adc[x]) && (voltage < adc[(x+1)]))
    //x = (x + dirOffset) % NUMDIRS;
    windDir = directions[x];

  • Here’s a link to an Arduino program I wrote that reads the wind speed and direction, and sends it back to the PC via the UART in readable text. The device works great, but the provided documentation isn’t much (to put it kindly), so even if you want to develop your own code, this might clear a few things up (or make it worse!).
    I also have a C# program that reads the COM port, and logs it all to a disk file (with time stamps) for later statistical processing (or whatever). Let me know if you’re interested, and I’ll post that.
    Good luck,

    • I’m putting together a website to attempt to document and help others build full weather stations… I’d like to add your code and invite you to be part of the project…

  • How long are the cables?

    • The cables from the wind vane and rain gauge are a little more than 9 ft. The anemometer is quite a bit shorter as you can see in the pictures above.

  • hi, i am interseted in using the weather station (and the weather board)with the arduino ethernet shield.Is that possible to happen and how it will be the best to put together the three boards (arduino+ethernet shield+weather board) I mean which comes first is it of any importance?if you know any tutorial regarding that I would be grateful too thank you in advance!

  • Hi. This product will be available again?

    • We’re sorry for the delay, we’ve been waiting for our current order to be fulfilled for some time. We do expect to be getting more sometime in March. Be sure to click the “autonotify” button above to receive an email as soon as they’re available.

  • I made a weather station that reports current weather info to an LCD plus sends info to my local network where it’s stored on a mySQL database and used to generate weather data charts that can then be displayed on websites.
    I’m trying to sort out all the information that used to make it work and I’m posting things as I go.
    Check it out and perhaps help me out to clean/ optimize the code (there’s a lot of things still to do).
    I also used the STH15 temperature and humidity sensor on top of these weather sensors. All works pretty well!

  • got it to work fine with Steve’s code:
    received debounce on an external interrupt for rain, had to add this code to get it to work…i think/hope
    // Interrupt handler for rainmeter. Called each time the reed
    // switch triggers (one tip of bucket).
    void countRainmeter()
    static unsigned long last_millis = 0;
    unsigned long m = millis();
    if (m - last_millis < 200){
    // ignore interrupt: probably a bounce problem
    last_millis = m;

  • I’ve completed and submitted a more useful datasheet. Hopefully they’ll have it on here soon.

    • Hey N1VG. I was wondering if I could get a copy of the updated data sheet. I’m not sure if the one on the site is the correct one or not. I have one of these devices and am trying to trouble shoot a couple of points. Any help would be greatly appreciated.
      Thanks in advance.

  • Can anyone confirm which colored wires go to the anemometer and which go to the vane? I want to connect to arduino as well. Not sure which colors go to ground versus pins.

    • I would love to know as well.

      • The color isn’t as important as the wire’s position in the connector. If you look at the clear connector, you can see where the colors line up. The circuits use the outer pair and the inner pair, so you just need to know which wires were at those positions in the connector. Since the circuits only involve switches and resistors, the polarity doesn’t matter, so you can ground either end of the pair. Good luck!

  • Sure. I put the executable in the same directory. You’ll need the .NET runtime unstalled to run it. It assumes you’re in COM port 13 (that’s just where I’ve been testing), so you’ll get an error at startup (unless you happen to use 13 as well). Just keep going, and set the port to whatever you are using.
    If you want to tweak the code, I included the whole C# project too. It was done under C# Express, so to compile it under regular Visual Studio, you’d just have to start your own project, and copy in the files. If that’s a pain, I could also produce one for that version too. I think I still have it around.

  • The data sheet claims one trigger for every revolution of the anemometer. I have verified on 2 units it’s two triggers per revolution. working anemometer code posted at

  • How fast of a rainfall event can this rain gauge keep up with?

    Where I am interested in deploying this, central Texas, we can receive 6-12" of rain in under an hour. Will these reed switches report with that accuracy?

  • Hi, how uniform are the anemometer samples metrologically? Do they undergo any kind of calibration? Is it possible to get the same set without rainfall. I need only wind speed/direction but if possibly more precise. Any pointers to similar sensors set are appreciated and welcome.

  • “ A wind speed of 1.492 MPH produces a switch closure once per second.” Can’t be right. That would equal a 8.363" diameter anemometer. Correct me if I’m wrong, the diameter is 5.5", so 60 rpm (1 RPS) = a wind speed of 0.98125 MPH.

  • Any good solution for temperature, humidity, and barometric pressure that can be added to this?

  • I am currently using this product to create a ground station for UAS (multicopter and fixed wing) deployments as part of a research project. I am utilizing the wind vane and anemometer sensors, and have found them to be relatively accurate. As mentioned by other reviewers, the anemometer does give two contacts per revolution.

    I have found the wind vane to only really give 8 directions, not the 16 as advertised in the datasheet. That is due to the magnetic switch design, which simply allows for the tertiary directions to be measured, but does not guarantee that those tertiary directions will actually trigger. I personally used a 9.9 kOhm resistor (just happened to be what was lying around).

    For the anemometer, I found that I needed to give a scaling factor to take into account the fact that the anemometer does not spin at wind speed (due to aerodynamic affects caused by the opposite side cup coming through the air and the inefficiency of the cup in catching air). I found that a scaling factor of approximately 0.099 works, but this is based on very crude testing with a car in a somewhat windy environment.

    The pipe on which the weather station is mounted has an OD of 0.800 +/- 0.007 inches. The plastic boss for the arm that holds the wind vane and anemometer for the pipe to mate onto is 0.731 +/- 0.006 inches.

    The code for my project is located at, under the folder WeatherStation.

  • I just released a C++ Arduino class supporting the SEN-08942 product on and I’m publishing an article about it in the September issue of Raspberry Pi Geek magazine. WeatherArduino Lives!

    The post is at:

  • having a hard time sourcing the voltage. I’m am new to this. just looking to grab the most basic data from the wind sensors. Thanks!

  • I put this together tonight and have one machine screw left over. Did I miss something? Also, there were two small screws, one I assume was for the rain sensor but where is the other one supposed to go?

  • This might be a stupid question, but everything included in this kit is waterproof right? not just the rain meter? how much water could the whole thing handle before it starts to go haywire?

  • There is one slightly misleading information regarding the wind direction sensor - it does not provide “true” 16 directions - one cannot assume a change in reading every 22.5 degrees. There are 8 “stable” directions with 8 intermediate directions - this is mainly to prevent a case where both reed relays of the main directions are off. It took me some time a communication with tech support to find this out. But otherwise, and understanding this limit, a very nice kit which I very easily interfaced to an Arduino (rain and wind speed go into the interrupt pins - use a small cap to prevent bouncing, wind direction into an analog input)

  • Help please: I want to connect this sensors directly to Arduino without the weather shield. Is it possible? Can you please help me with a connection diagram and a basic code?

  • hai., i have few problems that i would like to have advice from u guys. can anyone help me how to obtained the pulse/signal from the wind speed as i need the data so that i can convert it to a voltage,. i had discovered that the line cable indicates black - cable 1 colour for the ground and green colour -cable 4 is the output (correct me if I’m wrong). really appreciate your help.. tq

  • How about The accuracy on the wind sensor etc ? Is anyone running this and Can I get the link to access the data ? I would like to compare with one of our high end weather stations nearby. I read Nate’s tutorial.. I wonder that system still alive and transmitting the data. The reason I am asking one of my co worker told me this kit they sell on amazon with different brand labels and has some bad reviews. I have integrated Vaisala WXT 520, Davis wx and Onset HOBO above 2k price range weather stations for our customers with our proprietary hardware. Would like to interface cheap wx station like this on our current system ( or ardunio based open source system ) with some mesh networking if they want multiple stations and sell for school kids for a small price. I bought a cheap wireless lacross wireless weather station for $70 bucks on sale from costco with a gateway, Full price is $299. It is got everything mobile phone app, alerts system and etehrnet gateway, But it is hard to hack into that system to work with a development kit. The coolest thing is those sensors are wireless and easily you can mount. I haven’t installed out door but other sensors work okay indoor ans set up is easy. But we need to build a kit where kids can learn about weather stations. My company already have a back end and front end to get the data to cloud. We all the system to support sensors But our price is because we don’t have control over the off the shelf sensors We buy from 3rd parties. I need to know the accuracy of wind sensor etc before purchasing this. Idea is make a kit and target school kids specially to learn environmental monitoring not for profit. They can store data for free on our server and we can also provide data visualization on Google earth style open source map call Inteleview. Thanks If anyone can reply with more information regarding this product. I need to know the truth. Sometines people lie on the internet or they simply they don’t know what they are talking about. Below is my company web address.

  • Hi, could you tell me the weight of the kit?

  • Hello everyone. I am trying to design a circuit to wire this weather sensor up to a Raspberry Pi. I understand the wind vane needs to go though an ADC before going through to the Pi (I’m using I2C), but not sure what circuit to use to connect it to the ADC. Furthermore, I am unsure of how of what a circuit for connecting the rain gauge and anemometer to the GPIO on the RPi would look. I’m using a 3.3V supply voltage. The datasheet is not the most handy. Any help would be greatly appreciated. Thanks.

  • Hi, please tell me how can i connect this sensors with Arduino, i have no datasheet, and 3 connectors not 2 (not compattble with weather shield).

  • How can I supply a power to the weather meter, can you please tell me in detail what should I use? I want to link it with an arduino that the signal will be sent from the weather meter to the arduino!!

  • Your “Datasheet” doesn’t mention a speed limit for the anemometer… Will it work up to 150mph?

  • Just wondering how well this plastic will hold up to UV. I have had two other assemblies from another vendor and the sun takes a toll on the plastic. Eventually becomes fragile and breaks easily.

  • I’m wondering if it’s best to use the meters with the weather shield, or just cut off the RJ11’s and feed the wires directly to my Arduino? It may be more code-work, but it seems like it wouldn’t be too hard to just poll the data and insert some formulas. Any feedback?

  • I have been testing the wind direction sensor. I find that two of the sixteen positions do not register. In my case it’s wnw and nnw or 292 and 338. At one of the positions neither the 270 or 315 switch is closed and I get a full 5v at the arduino pin from the voltage divider. Has anyone had any success taking this apart and tweaking the switches or magnet to get better sensitivity?

  • Does the Rain Gauge anchors to its arm with just one little screw ? It seems unsafe to me… Or meybe i do something wrong ? Thanks

  • Hi! to connect the weather station with Arduino, ->

  • To connect the weather station with Arduino:

  • I’ve hooked this up as described using a 10K ohm resistor and 5v power source but for some reason the measured voltage seems to stay constant. I check the other pins incase I was using the wrong one but I get the same result.

    Does anyone have any suggestions?

  • Looking for the way the rain gauge works, i think there are two options:

    a) Each change a tiping bucket makes a short pulse, so with the pull up resistor we have, it makes a pulse from logic 1 to logic 0 and back to logic 1. Then the circuit we all use is correct.

    b) Each tiping bucket position makes either logic 1 or logic 0. So, since we use a pull up resistor, we count only the change of logic 1 to logic 0. After a change from 1 to 0, and after more rain, the gauge will change to logic 1 (this will NOT increase microcontroller’s rain counter) and then, after more rain, the gauge will change to logic 0 (this will INCREASE microcontroller’s rain counter) .So, we are only counting changes of logic 1 to logic 0 and NOT counting changes of logic 0 to logic 1. Do we miss some rain, this way? The question: If this is the way to gauge reed relay works, why not connect the rain gauge to a microcontroller port with interrupt on change capability and count both changes???

    I am asking that, since i also saw the recent change in the Sparkfun’s weather shield board software (after a user’s real work measurents). I mean the increment of the rain value of each pulse.

    So, with which way it works?

  • When is this going to be available again ? :(

    • As soon as we receive our shipment from our supplier! Check the “Notify Me” button under the stock levels, and you’ll receive an email as soon as it is back in stock.

  • Do you really expect the next shipment to arrive on Christmas day?

  • Hello sparkfun,

    I am waiting for this product to be available for purchasing for more than two months. Come ooonnnnnn :(

    • We’ve been trying our hardest! Unfortunately, our supplier has an extremely long lead time. We’re waiting as impatiently as you :( You can always add it to a back order and have it ship as soon as they come in.

  • hello …. sell the sensor that measures wind speed separately? …. if so, how much?

    • Sorry, our source only offers these as complete units. If you look through these comments, you may find other sources for individual replacement parts.

  • Has anyone used these in freezing temperatures? I’m somewhat concerned about ice damaging them, but would like to leave it up year round if other have had success.

    • I have had the wind sensors up on the roof here in southern Norway since December 2012, and they have been working fine for about a year now, in temperatures down to -19 C (-2 F). I did not put the rain sensor up there, as it gets filled with debris from the trees around here, and I have to clean it out occasionally. As it isn’t heated, it doesn’t work below freezing, however, it starts working again once thawed out.

      • Has anyone used in temperatures around the -40 degree mark, and what is the max wind speed that it is rated for? I want to use one on my house, but the ideally of climbing 30 feet into the air at -40 when things start going funny is less than appealing.

        Thanks for the info.

  • HI there, anybody here knows how much current will this take? I’m asking because I want to add a LiPo battery and Solar charger to my project in order to let it work off the grid.


  • Whilst I understand the interest in assembling projects for oneself, it is possible to buy a finished product including these same sensors, together with a tempature & humidity sensor & RF transmitter unit (so that all the sensors can be connected wirelessly from outside), together with an RF receiver, LCD touch-screen display and data logger (lasts many months depending on sampling frequency), and a USB interface for little more cost ($100). See . Or without the wind direction module or USB interface, it’s only $65 ( or $45 for B-Grade (opened box customer return)

    There are links on their site for buying individual sensors as spare parts.

  • I would like to come back to the issue of wind speed sensor.

    Since the sensor makes two pulses for a full revolution, there was a small issue about the way of calculating wind speed.

    I mean either use a pulse or two pulses for calculating a wind speed of 1.492 MPH (or 2.4 km/h).

    So, is there any verification about this?

  • Hi, I have a problem with the wind direction vane. I connected it according to Steve sketch, with a 10k resistor to wind vane. The wind vane doesn’t work properly. I mean that some wind directions are not shown. i.e. S and NW are missing. I disconnected the RJ11 and checked with a tester all the resistors values: I can read all values correctly according to the data sheet but when I connect the plug to arduino, some of values are missing. Can you help me? Thank you for your help and … I apologize for my bad English. Piero

    • I have the same problem with mine, as well; monitoring the values while rotating the vane reveals that those two positions literally don’t report any value! Any assistance would be greatly appreciated…

      • My problem is resolved: The code from here: Is superior. It supports all 16 positions on the windvane and refers to a typo on the data sheet with respect to the specific resistance values. I’m finding that the cutoffs for some of the angles are a little narrower than others, so I might tweak the values, but this is clearly the way to go. Good luck!

        • I’m trying to get my weather station running, using Mr. Kessler’s code, but I’m having problems taking his code and making it work with my setup. Can you help me understand his code, please?

          Thank you-Dave Anderson

  • HI,

    Want arduino code to read wind speed and wind direction on a com port.


  • Halleluiah!

  • A simple google search of the product code SEN-08942 returned this:

    I didn’t complete the order, but it seems they have it in stock, at a bit higher price though.

  • Can someone write a list of possible weather station sensors. What things could be valuable to track?

  • Here is another source for anemometer/wind vane, albeit expensive at $100.

    This looks like a very well made device. Reading the description, someone should be able to adapt the weather board to read this. I haven’t tried it and make no promises, but it looks interesting.

    They have a rain bucket too, but I haven’t investigated it.

  • What is the prognosis for getting these back in stock again? still looks like a great core for a custom weather station.

    • We’re sorry these remain out of stock; there’s a problem in the supply chain that is delaying our current shipment. We’ll have them back on the storefront as soon as they arrive.

  • These appears to be the same sensors that the Ambient Weather WS-2080 uses:

    They work and will probably last awhile for most applications. But they are not “rugged.”

    • I bought a set of these as “WS-2080 replacement parts”. You can find them on ebay for about $20 (plus shipping) for each of weather vane, anemometer and rain bucket. Search on “WS-2080”. Leave the “Ambient” off the search or all you will get are weather station packages, not the parts. I have confirmed that the vane and anemometer work with the Sparkfun Weather Board. I have not confirmed the rain bucket yet.

      When you buy them this way, you don’t get the mast or the cross bar, but this is all DIY right? At least they are available.

  • How did you calculate the 50.74 ? const float WIND_RPM_TO_MPS = 50.748803; // divide RPM by this for meters per second in the USB Weather Board V3 firmware?

    The datasheets states that 1 click/s gives 2.4 Km/h or 0.67 m/s. Assuming 2 clicks per rotation: 1 Rotation/s corresponds to 1.3333 m/s now if you have RPM the speed should be (RPM/60) * 1.3333 m/s or RPM/45

    How did you come up with the 50.74?

    • Real-world testing. I hacked a USB Weather Board to also accept GPS data (via softserial and TinyGPS), and output/logged GPS speed and anemometer RPM. We then drove around with the weather meters sticking out of Robert’s fast car on a windless day, driving different speeds in different directions. Since the anemometer is a mechanical device with inertia etc. there are always going to be some inaccuracies, but 50.74 was an extremely good fit between the GPS speed and the RPM data.

  • I’m trying to test the rain gauge portion of this product. By my calculations, to get ½ inch of rain, I’d need to pour 2 oz. of water in the gauge.

    Calculations for cubic inches for ½ inch of rain: (H x W x L): 1.875 L x 4.25 W x .5 H = 3.98 Cubic Inches

    Conversion from cubic inches to US Fluid OZ: 3.98 * .55411 = 2.2 OZ.

    Only, my rain gauge read 1.5 inches, not .5. I’ll try de-bouncing the switch to see if that helps. Any other thoughts would be greatly appreciated!

    • Ok. Adding debounce code worked; well sort of. 2.2 Oz of water shows .23 inches of rain on the rain gauge, not the .5 inches my math calculations predicted.

      • What I’d recommend at this point is, if you’re sure your debounce code is operating correctly and that your weights and measures are accurate, is to use your result as the calibrated value for your sensor. That’s what we do here.

        • Thanks MikeG. Great suggestion, only, I’m not exactly sure my math is entirely accurate. My gut says that my math is off, not the meter (nor my debounce code). Math isn’t exactly my strong suit. Has anyone else tried to verify the accuracy of this device?

          • I did almost the same test when working on the firmware for the USB Weather Board, so you might take a look at that code. I came up with the number 0.0086206896; multiplying bucket-tips by that number should give you inches. That assumes that -my- math was accurate as well, which isn’t guaranteed either. ;)

            • Hey Mike. Thanks for the feedback. I ran 8 oz of water and got 135 bucket tips. So, while your ‘rainfall per bucket tip’ number is ‘0.0086206896’, mine turns out to be about double that at ‘0.014814815’. Is there any chance you can run 8 oz through your gauge and give me your bucket count?

              So, check this out. When I dump 8 Oz of water into the sensor (as fast as it will take it), the gauge registers .8 inches of rain. Turns out, that rate is the equivalent of 30 inches an hour (probably over-loading the gauge). The max a hurricane can deliver is about 6 inches an hour. Plus, at 8 oz. of water, I’m expecting it to register 2" of rain, not .8. Oh joy!

              On the advice of a friend, I drilled a couple of holes in an unused jar of peanut butter (one of my favorite scientific instruments by the way) using a 1/16" drill bit. Now, 8 Oz. registers 1.33 inches of rain (at a rate of 30 inches an hour). This is still raining faster than a hurricane, so I’m guessing that I’m still overloading the gauge. Next, I use a needle to create the smallest hole I can possibly imagine. Now, I get 1.43 inches of rain of a rate of about 5.5 inches per hour. I’m unsure on how to make it any slower. But, the good news is that multiple tests yield about the same results. Only, mathematically, 8 oz of water should be 2 inches of rain, not 1.43. So, I’m still stumped…

              Mike, thanks again for the feedback!

              • When I did it, I effectively put about a liter of water through it using an eyedropper, because I was concerned as you are about the rate throwing things off (and rainfall is typically at a very low rate).

                I don’t have time at the moment to re-run the test, but my math was: opening area of 12.7392", so volume to equal 1" is 12.7392 cubic inches = 208.758ml, which took 116 counts on average over several runs. Your mileage may vary. =)

                • How did you come up with an opening area of that size? Has the rain gauge changed in size? The opening for the one I purchased from Sparkfun is 1 7/8" x 4 ¼". That’s about 8 square inches.

                  • You’re right; I wrote down 2.95" wide, it should be 1.95" wide. D'oh!

                    The updated numbers should be 4.33" x 1.95" - 0.2" corner radius = 8.4092 square inches = 8.4092 cubic inches for 1" of rain = 137.802 ml = 4.66025 (US) ounces. I’ll have to do another test and update the code. =) Thanks for the second pair of eyes!

                    • Great! This sounds like progress to me. Seems as if our calculations about the number of ounces needed to get an inch of rain now match up to mine. Please post your revised ‘rain inches per bucket dump’ number when you get a chance. I’m really hoping I’m not crazy and it’s close to ‘0.014814815’.

                      • Good news. I ran my first ‘real world’ test against a rainstorm last night. reported .40 inches (they round to the nearest .05), and using the ‘0.014814815’ factor above, I recorded .44 inches of rain. I’m pretty happy with that result.

  • I would like everyone to know that the datasheet for the wind vane’s output voltage is wrong for the 315 degree direction. If you do a voltage divider using 5 V…. ((64.9k * 5)/(10k + 64.9k)) = 4.33V. Not 4.78 V. Please have this corrected.

  • I see that some people seems not sure about the anenometer as it closes two times for each circle. Some claim you need to change the formula for calculating the wind speed and some say you don’t-

    I’m going to put together a weather station using this kit and I’ll be comparing it to a Davis Weather Wizard III which is hopefully displaying the correct wind speed. So then I can tell whether the data sheet is right or not.

    Though it’ll probably take some time before I can test it as I have a lot of other stuff going on right now.

  • What are the dimensions of the package delivered by mail ?

    • I ordered mine from a Swedish Sparkfun retailer. So I’m not completely sure the package are the same. But mine came in a box with the dimensions 31 x 31 x 12 (cm)

  • Hi- What is the maximum speed of the Cup Anemometers? Do you think it will handle 100mph gusts?

  • Could you list the weight of these parts? I am interested in mounting these on my arducopter. I am looking for the weight of the wind vane, anemometer, and the wind meter mounting bar.

  • I would like to know when will have new product availability?

  • Hi, do you have an estimate how soon backorders will be fullfilled?

  • Hi There:

    I have connected these sensors to your USB weather board. I’m using the stock firmware. I’ve enabled the “weather meters attached” option through control-Z and saved the settings.

    I get no readings for either wind speed or rainfall. Wind direction, however, works fine. I have verified that my connectors on the USB weather board have proper continuity, i.e. no soldering screw-ups.

    I’ve also ensured that the RJ11s are inserted properly (anemometer to wind vane, both rainfall and wind connectors into the weather board) but it’s a “no go”.

    I hear the reed switch on the anemometer clicking, and the rainfall gauge teeter-tooter cycles.

    I am going to scope the outputs of both the anemometer and rainfall gauges (through an external 5V), but thought I would inquire in parallel in case others have had this problem. Nothing I could see in the product comments, however.


    • Hi Again:

      Well it looks like I needed to restart the weather board after changing the settings. After typing the last message I went downstairs and fiddled with the sensors individually. They seemed to work.

      I reattached them to the weather board, and all was well. It seems that the weather vane doesn’t require a board reboot, but the other two sensors do.

      All is well now!


      • Very helpful! I was experiencing this same thing, and your comment saved me. Thanks.

  • I have a strange problem:

    I have the anemometer and vane connected to each other, so just one RJ11 connector to my arduino board.

    If either the anemometer or the vane is connected I get the right readings.

    If I connect both devices, I only the anemometer readings and 0 from the vane.

    I use for both a 10K pullup resistor and it’s all @ 3.3v

    I already tried to switch (ground to power and power to ground) the cables of the anemometer (I thought they may use the same ground?)

    But this doesn’t help…

    Anybody any idea?

  • I noticed that wind strength meter makes two contacts (pulses) for each full circle. I was thinking maybe it should make a contact (pulse) for each circle.

    It can be checked even with the multimeter.

    Is that correct? Or mine is broken?

    • Yours is working correctly, or at least functioning identically to the ones we’re using.

      • Thanks Mike,

        So, my sensor is not broken. It is normal to make two pulses per one full circle. Your answer made me relief!

        For the history: For anemometer i used 10K resistor pull up and a 10nf to ground for filtering. For wind direction i used 8.2K resistor pull up and a 10nf to ground (all in 3.3V circuit).

        Both are working very good! I am recommending these sensors to anyone wants to make a DIY weather station!

  • I bought one and connected to my USB Weather Board. All sensors but Rain Gauge seem to work fine. I have a trouble with my gauge that it sometimes counts up without any rain. Yesterday, although there was no rain and humidity was less than 60%, it counted 25 times in a day!

    Does anyone have the same problem?

    • Also be sure that the weather meters are mounted securely. If wind gusts move the rain gauge box, the teeter-totter inside can shift causing a false reading.

      • I’m sure that sitting of this rain gauge is very steady, because it is on the ground to examine what is the problem.

        • How long are your cables, and what type are they?

          • I don’t change from RJ11 cables originally connected and don’t extend them, so their length are probablly 10 fts long.

            • OK, that all sounds fine. Are you running the stock Weather Board code, or did you write your own code?

              • When I had this problem, the firmware of USB Weather Board running on my board was your v1.2 code.

                • I haven’t seen this on any of our test units, and without knowing more about the spurious pulses (sampling them with a logic analyzer, etc.) it’s hard to advise ways to mitigate them. The Weather Board senses the rain gauge by connecting one side of the switch to ground, and the other side is pulled up by the 20K weak-pullup resistors internal to the ATmega. You might try adding a smaller / stronger pullup, e.g. 1-10K on the pulled-up side (see the schematic). And if they’re brief pulses, it may be possible to mitigate them by adding a low-pass filter as #317056 mentions, or in firmware via timing. I’ll keep an eye out for this problem, and let us know if you find any causes or cures.

                  • From my observation, these pulse were NOT always scattered. Sometimes they were scattered but at other times a few pulse came to my board for a minute.

                    If you haven’t seen this problem with your test board, I want to know why I did and you haven’t. Environmental factor? Cs137 from Fukushima? (Definitely no. I confirmed that the place where my board sits is not contaminated by radioactive. - it is only 0.05uSv/h)

                    Anyway, with my modified firmware, any false pulses have been disappeared. (I should say “ignored” instead of “disappeared”.)

    • I found a solution: you may want to use a low pass filter for the raingauge and anenometer:

      here is a link to a plan:

    • i have the same problem and found no solution yet.

      • I modified the firmware to solve this problem.


  • I bought one of these a while ago and it sat for too long, waiting for the weather station project to come to the top of the pile. Then I got a chance to make an interactive LED sculpture for the Source Maui festival. This became Logo Glowego ( - 7 arduinos, 12m LED strip, weather station, BMP85 barometric pressure, SHT1x temp/humidity, Sharp IR Sensors, etc. Wind vane controlled the color of light strips. Anemometer controlled amount of strips lit (inversely). Rain gauge was not used for this unfortunately. Given it was one of the wettest events in memory at Camp Ke'anae it would have been good to record the wind & rain.

    Anyway, I like modular code so I made a library to handle the Weather Station. Code is available as part of overall Logo-Glowego…

    • Hello, Can you provide, please, an example code for your library? Do you plan to add a Rain module code?

    • My wind direction seems to be off by a consistent 45 degrees when compared to a compass. Any thoughts?

      • Never mind. It seems that the wind direction is not based on magnetic north, but rather on how the instrument is mounted. On my unit, the cross-bar must be oriented East/West with the wind vane mounted on the western-most end. Urg…

        • I think may be a type in the wind direction table. I think the voltage reading for 315 degrees should be 4.34 volts, not 3.43.

  • Has anyone tried this using a propeller

  • Does anyone know where to get just the anemometer unit?

    • Try to get one from here:

      Here is some info about hooking it up to Arduino:

  • A new(er) arduino based project using this product - Wireless (RF12) with SHT11 and web server (ENC28J20) all be it primitive at this point.


  • Aww - every time I check, this product is in backorder. I found it here: Sorry SparkFun, I have to go elsewhere for this item, but I’ll be back here for more!!!! :-)

  • How heavy is this thing?

  • Here is a student project using the Weather Meter with mbed to tweet weather info
    It also uses these handy RJ11 breakout boards to hookup the cables from the Weather meter. They have screw terminals, but you can also solder on header pins for a breadboard.

  • There is an error in the voltage/resistance table for the wind vane. At 315 degrees, the voltage should be 4.33v not 4.78 as shown. I made a spreadsheet to run the numbers at 3.3v and different load resistor and noted the error.

  • Hi,
    Please add more to the stock because they sell out very fast!

  • Anyone have any advice on how they are connecting this to an Arduino? Didn’t realize it had telephone style connectors.
    Are people connecting the anemometer to the wind vand and then just cutting off the end of the cable from the wind vane?

  • Mind posting pictures of this on a black background?

  • Tycon Power Systems might be where this thing is coming from.
    You can order the sensors individually from here or here.
    I recently ordered the anemometer and wind direction sensor from Beezwax Products as I already have a rain gauge I can use. They were shipped the same day.
    If you need all the sensors then it’s better to just get the whole thing from SF.

    • Hi everybody,
      I don’t understand why the tycon power systems requires 2 AA batteries for the sensor. The sensor here doesn’t require any power supply (am I right?). I saw that the only difference between the system of sparkfun and that of tycon is the sensor of temperature/umidity. can the batteries required for that?

    • It really does appear that the sensors come from Argent Data Systems, or at least they have them manufactured and then put their name on it. The sensors you linked are not identical, though they are pretty close.

      • The sensors do indeed look a little different on those two websites I linked to. But it turns out the pics must be a little outdated or something. The sensors I received look like they came out of the exact same molds as the ones SF sells. I compared the enlarged pics and can’t find any differences down to the smallest detail that I can see. They have the same hookup as well.

  • I ordered this on February 21 directly at Argent Data Systems, thinking I would be crafty and avoid the supply chain charlie foxtrot that seems to have swept through a lot of the open hardware sites in the last few weeks. However, the order there is still sitting on “processing”, and I’m just about ready to cancel it and wait until the light turns green here at Sparkfun. Sheesh.

    • The long wait is over. My sensors shipped from ADS on March 14 directly to me. I wonder how long it will take for them to get to SF?

  • Will it be available again?

  • Could someone please post some code or suggest a way to way to generate an arduino script that prints the number of rain bucket tips in the last 24 hours? With or without a RTC. I see a few stubs in these comments but I cant get them to work- TIA

  • So, let’s see now… Say I put this thing up on my roof somewhere. (Funny, it looks sorta like a lightning rod) Then I connect the little wire from the wind direction thingy to an analog input on my MPU chip.
    So then I suppose I better plan to replace that chip every time there’s a thunder storm anywhere in the county. Guess I better buy in bulk. :)
    I’m sorry guys, but this is a really lame design. It’s just a total non starter.
    Okay, so tell me more about this reed switch and resistor assembly. Can I easily hack the resistors out of it and just run more wire, or is the whole mess potted or something like that? If I can just hook up the reed switches directly to some nice robust blob of MOVs, gas tubes, and optoisoloators this all stands some chance of being workable. Otherwise it’s just a rig for letting the magic smoke out.

    • @Jeff: Just put a lightning rod above the weather system and run it to ground. Or, don’t stick it quite so high and live with slightly less accurate results.
      Or, buy a magic smoke recovery system. I’m sure ThinkGeek will have one available around 1 April 2011.

  • Any sign of these coming back into stock anytime soon?

    • Looks like we are working to get our hands on some more. But at this time there is no specific arrival date set. Very sorry.

  • Re: Wind Speed per closed contact count …
    I think I’ve answered my own question from back on April 27th regarding the Wind Speed per closed contact count. Today I pulled up some info on cup style Anemometers. According to the original inventor of the cup Anemometer, the cup velocity should be ~1/3 that of the wind. That gives an approximate value of 1.6 mph for this Anemometer to close a contact once per second (with two closed contacts per revolution).
    I will be using the datasheet’s value of 1.492 mph per 1 closed contact per second.
    To N1VG – would you please confirm this?

  • Domos: _ A wind speed of 1.492 MPH (2.4 km/h) causes the switch to close once per second. But I do not understand, I tested the anemometer and I have 2 contacts per revolution. Can you confirm the number of contacts per revolution ?_
    I have the same question as Domos. The values given in the datasheet appear to give wind speeds that are double. I checked my readings against a 10-yr old Kestrel 3000 hand held meter, and the wind speeds were ½. I have adjusted my values to 0.746 mph / count, where the counting is done on the Falling value, or “attachInterrupt(INTERRUPT_ANEMOMETER, countAnemometer, FALLING)”;
    Has anyone else found this to be true???
    To attempt to answer some dimensional questions with the model I received: 1) Tube diameter = 0.795" or 20.4mm. 2) Distances from center of tube to centers of Anemometer and Wind Dir: ~5". 3) Distances from center of tube to max distance out for a) Anemometer: ~8.5", b) Wind Dir: ~9", and c) Rain Gauge: ~9.1".
    Steve, thank you for posting your code!! Very helpful.

  • Anybody know the external diameter of the pole that comes with this?

  • Hi
    What do you think can the maximum cable length be from ardruino(powered by with external 5V power supply) to weather meters, if i use cat 5 cable connect to ardruino’s attachInterrupt/analogue pins, will it still work ok at 65 feet?

  • I bought the “Weather meter”.
    The datasheet say for the anemoter:
    The cup-type anemometer measures wind speed by closing a contact as a magnet moves past a switch.
    A wind speed of 1.492 MPH (2.4 km/h) causes the switch to close once per second.
    But I do not understand, I tested the anemometer and I have 2 contacts per revolution.
    Can you confirm the number of contacts per revolution ?

  • What is the best way to connect the wind vain and anemometer to the Arduino? it seems like it might be easier to connect them separately instead of plugging the anemometer into the wind vain. I am unsure which wires coming from the wind vain correspond to the anemometer and which to the wind vain. any advice? Thanks!

  • saustin:
    I also have a C# program that reads the COM port, and logs it all to a disk file (with time stamps) for later statistical processing (or whatever). Let me know if you’re interested, and I’ll post that.
    Good luck,

    Thanks for the code… it should help anyone (or not!!! heheh) to get started.
    I am interested on you program. Can we have it?

  • juan329: marcelino thank you for answer my question
    Just wanna help… very much welcome.
    Actually I have already created a DIY version, however it so hard for me to calibrate. This is why i am now considering this product. Not to mention its good look and the assembly aesthetics.
    have you already purchased one? perhaps you can give me at rough dimensions of the other parts. i really don’t get what 28.5x8" means… :D

  • juan329: I have a doubt regarding Anemometer, can you tell me if it need external power? (the anemometer acts as a switch and the volt present in the pin 2 will be present in the pin 3 when the anemometer will turn around) or just I need amplify the out signal
    Can you explain me how working the anemometer?
    I hope your answer
    thank you

    I guess it is just a reed switch which closes when magnet is near during rotation. it is just a simple close-open switch. So, external power is not required.

  • Can i have the dimensions?
    28.5" x 8" is so vague.
    what is the cup size of the anemometer? what is the total radius? etc..
    This are just a required parameters for my project. if it would fit, then i will purchase right away.
    The good thing about this simple set is that it uses a standard way of measure weather. I am just wondering on its dimensions.:)

  • I have a doubt regarding Anemometer, can you tell me if it need external power? (the anemometer acts as a switch and the volt present in the pin 2 will be present in the pin 3 when the anemometer will turn around) or just I need amplify the out signal
    Can you explain me how working the anemometer?
    I hope your answer
    thank you

  • Those are the A/D readings assuming that the vane sensor is on the lower (grounded) side of a voltage divider with one of the resistors at the head of the columns on the top (Vcc) side, and that the A/D resolution is 8 bits.
    E.g., for a north wind (33K ohms) and a 10K dropping resistor, 255 * 33K/(10K + 33K) = 196 counts. There’s certainly no requirement to use any of those resistor values but they’re quite reasonable.
    It’s not the clearest data sheet I’ve ever seen. Not the worst, either. ;-)

  • Nice, but give me more detail about this product (pins detail and who make this).Thank you for your help,I hope

  • The wind vane pot values are very confusing. Please explain further and/or clarify in the datasheet.

    • The wind vane outputs are discrete, not continuous, with eight 45-degree sectors more or less centered on the compass rose. Different resistors are switched in-line for each sector. One caveat: the boundaries are not crisp and you may see an open or an overlap (with two resistors in parallel) for a few degrees around each sector edge.
      Values in K-ohms:
      N 33
      NE 8.2
      E 1
      SE 2.2
      S 3.9
      SW 16
      W 120
      NW 68

      • Can you please explain the other wind vane values listed on the datasheet. For example:
        “Dir Res 10k 6.8k 4.7k
        N 33k 196 211 223"
        Please explain the significance of 196, 211, and 223. Thanks

  • Is it possible to find out who makes this?

Customer Reviews

4.5 out of 5

Based on 6 ratings:

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2 of 2 found this helpful:

Works, but needs code samples and updated data sheet.

anemometer - The data sheet is incorrect about one trigger per revolution, mine outputs two. I finally got working code together. Now will get direction working.

3 of 3 found this helpful:

Rpi Weather Station!

I’ve always wanted to build a weather station. Well, I bought this unit and began my journey. Before it arrived, I had 2 Temp sensors and 2 humidity sensors working with Python programming. The weather meter arrived in a little box? Yes, it is about 2 ft tall and easily put together. Use the available pigpiod daemon (free download) and then sample that wind meter, or rain gauge up to 5000 times a second with a Rpi 2. I’ll catch wind speed well over 150 mph easy or until it blows away. LoL.. Awesome. Sensors are now running at 150 ft from the house using Cat5e. Running sensors are Wind speed, Rain gauge, 3 (DS18B20) sensors, 2 humidity (DHT11 & DHT22), and a BMP180. With 11 sensors inputs running and displaying graphics on a HD TV, the Rpi is running 15-26% CPU.. What fun and a great challenge. I will be sharing this adventure with a Electronics 101 summer camp Next week June 15, 2015. Python coding comes by various vendors and code enthusiasts. Make it work together and use purdy graphics!…You can do it… Programming can take a couple of weeks to come up to speed. I think this kit will last for some time. Being a fairly small unit, it will have a small wind load. Make sure you mount the rain gauge securely. You can get false readings it it rattles.

Mike KD0ZW

Easy to install

I had an existing Weather Shield on an Arduino uploading data to the Xively service. After soldering on two RJ11 connectors and fixing the weather meters outside, I added wind and rain to the data. I was most interested in rain (for horticultural reasons) and it now reports ‘rain in last hour’, ‘rain in last 24 hours’ and ‘rain to date’. Really handy.

Very Happy

I was very happy with this product. All components are working correct. the most important the deadline was confirmed