False wind speed: measured 120km/h but actual highest gust is less than 40km/h

we have heavy rain for the past few days, I noticed during rain time, a wrong wind speed of 78km/h gust recorded, but actual wind gust for that time is less than 40km/h. I have another anemometer installed side by side. Also I have a government weather station within 800m away and it confirms my other reference is correct. The rain measured is also much less. this happen when it is raining. seems normal when there is no rain.

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Hi Henry. Thanks for joining our forum! It’s nice to have someone from Fine Offset/Ambient on the forum, providing feedback on our smart weather stations.

Looking at your data, this looks like the classic “rain on plate” issue - drops of water can interfere with the ultrasonic signal, creating erroneous readings. That was a relatively rare but still significant issue with early versions of our SKY device. There is quite a bit of discussion on the topic here on this forum.

For several months now, we have been applying a long-lasting superhydrophobic coating to the sonic reflector on all new SKY units which has virtually eliminated the issue. If you are experiencing this issue chronically, we would be happy to replace your SKY unit.


Is there a kit that is sold or will be sold for applying this coating without having to swap sky units? I’ve had the rain/wind issue only a few times but would like to make sure it doesn’t happen again. If there is a way to buy it from weatherflow or the product they use that would be great.


Yup, I too would be interested in that since I can generally count on some over-the-top gusts with some significant rains.

HI, dsj.

Thanks for your quick answer. I can give this to my daughter to bring it back to US in Aug. I will be fine if you can repair the sky sensor and send it to her after your repair. Good to hear you have a solution on this. Can you tell me the address for sending the device back?

Hi Henry. Please open a ticket with support@weatherflow.com and they can take care of you.

We have looked at a field-serviceable option but it’s unfortunately not practical - the coating needs to be applied with specialized equipment under controlled conditions. If you’re experiencing the rain-on-plate issue regularly, please open a ticket with support@weatherflow.com and they will take care of you!