# Wind speed run amok **URL:** \ **Category:** Tempest Owners\ **Tags:** tempest\ **Created:** [June 25, 2020, 3:42pm UTC](https://community.tempest.earth/t/wind-speed-run-amok/7260 "2020-06-25T15:42:01Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![tomw\_mail](https://avatars.discourse-cdn.com/v4/letter/t/bc8723/32.png) [@tomw\_mail](https://community.tempest.earth/u/tomw_mail)\ **Post date:** [June 25, 2020, 3:42pm UTC](https://community.tempest.earth/t/wind-speed-run-amok/7260/1 "2020-06-25T15:42:01Z")
Late yesterday, we had very heavy rain, and around 5:30am this morning, the wind speed went from near zero to about 10 – all 3 values (gust, avg and lull). With little variation, that lasted for a couple of hours, until 9am, when suddenly the gusts went up to 25-30, the avg around 20, and the lull in the upper teens. I did a visual inspection (it is 20’ off the ground) and just noticed lots of water droplets around the sides. Just before 10am, the speeds all dropped to a more reasonable 2-5mph. During the entire time, the actual speed was less than 5mph according to my nearby, old anemometer… Is it possible water got onto the transducers and messed up the sensing? Or something else? Thanks for any insight! ---
**Author:** ![peter](https://sea2.discourse-cdn.com/flex020/user_avatar/community.tempest.earth/peter/32/1365_2.png) [@peter](https://community.tempest.earth/u/peter)\ **Post date:** [June 25, 2020, 4:03pm UTC](https://community.tempest.earth/t/wind-speed-run-amok/7260/2 "2020-06-25T16:03:02Z")
> [@tomw\_mail](#): > > Is it possible water got onto the transducers and messed up the sensing? Or something else? Thanks for any insight! Yes, unfortunately this is completely possible. The transducers do have a special coating to help stop this from happening, but with heavy rain, light winds, and high humidity, water can interrupt the sonic paths leading to spurious wind speeds. As you saw though, when the water is eventually blown away the readings should return to normal. ---
**Author:** ![gizmoev](https://sea2.discourse-cdn.com/flex020/user_avatar/community.tempest.earth/gizmoev/32/941_2.png) [@gizmoev](https://community.tempest.earth/u/gizmoev)\ **Post date:** [June 25, 2020, 8:31pm UTC](https://community.tempest.earth/t/wind-speed-run-amok/7260/3 "2020-06-25T20:31:42Z")
@tomw_mail is this on a SKY or Tempest? If it is a SKY, is it one with the super hydrophobic coating in the wind gap or is it shiny smooth like the rest of the unit? ---
**Author:** ![iladyman](https://sea2.discourse-cdn.com/flex020/user_avatar/community.tempest.earth/iladyman/32/2305_2.png) [@iladyman](https://community.tempest.earth/u/iladyman)\ **Post date:** [June 26, 2020, 2:45am UTC](https://community.tempest.earth/t/wind-speed-run-amok/7260/4 "2020-06-26T02:45:48Z")
I took some video showing the behaviour of water on the special coating. This is on a ‘Sky’ but I assume the Tempest will be similar. There is lots of discussion about the problem on this forum, you could use the search to find it. If your pole is easy to give a swing from the ground you might be able to move the water drops and see if the wind reading changes. In very strong wind they get blown off but light wind they can bobble around sitting on the lower surface. Here is one example: > [@Cleaning and maintenance of Sky unit](https://community.tempest.earth/t/cleaning-and-maintenance-of-sky-unit/2428/11): > > Hi @WFsupport, How should we clean the special coating under the sonic transducers? This is a photo of my Sky #4834 after 52 days outside after some gentle rain: This is a video squirting water across it trying to clean it: [[Weatherflow Smartweather 'Sky' Cleaning the wind gap of the ultrasonic anemometer.] ](https://www.youtube.com/watch?v=sNtFl7CSpHI) This is a photo after the squirting: And after a gentle horizontal shake trying to remove the droplets: It appears to me that the spec… cheers Ian 🙂 ---
**Author:** ![tomw\_mail](https://avatars.discourse-cdn.com/v4/letter/t/bc8723/32.png) [@tomw\_mail](https://community.tempest.earth/u/tomw_mail)\ **Post date:** [June 26, 2020, 6:07pm UTC](https://community.tempest.earth/t/wind-speed-run-amok/7260/5 "2020-06-26T18:07:43Z")
gizmoev – this is a Tempest…just installed 2 weeks ago iladyman – thanks, Ian…interesting stuff – I had hoped to be “maintenance-free”…so it’s on a 10’ pole attached to an unused chimney…not too easy to get at… ---
**Author:** ![gizmoev](https://sea2.discourse-cdn.com/flex020/user_avatar/community.tempest.earth/gizmoev/32/941_2.png) [@gizmoev](https://community.tempest.earth/u/gizmoev)\ **Post date:** [June 26, 2020, 7:43pm UTC](https://community.tempest.earth/t/wind-speed-run-amok/7260/6 "2020-06-26T19:43:27Z")
During different coating field testing I found that puddling of water, as @iladyman shows, was the main culprit of strange wind behavior. I also found that sometimes a bubble of water would adhere to one of the sonic transducers, creating a lens effect, which would throw things off. The coating on the Tempest is a result of that earlier testing. My SKYs and field test Tempests have largely been maintenance free since the coating but your rain patterns and mine might be one of the differences. Hopefully it doesn’t happen too often for you.