Tempest wildly underreporting rainfall and rain rate under very heavy rain

We had pretty heavy rains here today. Peaked at 3.24"/hr for a total rainfall for the day, as of 8:30pm EDT, of 1.26" according to my CoCoRaHS gauge.

However, my Tempest fell wildly short, reporting only 0.65" and only a max of 0.88"/hr.
Battery voltage has been 2.48 or above all day.

Quite disappointing, to say the least. With light to moderate rain, it seems to be right on the money, but can’t keep up once it starts raining really hard.

Anyone else seen this?

I saw exactly the same order of magnitude under-report on Saturday. Today, my other 2 gauges report just over 1" , Tempest (after 1/2 lag) reports .82" It is in need of calibration.

I’ve seen this with the Sky. Usually after a few good storms it’ll calibrate and once it does it’s right on the money. If for some reason after multiple heavy rains you still have the issue you can open a ticket and they’ll troubleshoot and calibrate it if there’s enough data to work with!

Welcome to the Weatherflow community Derek,

I just had a look at your station and RainCheck ran … can you again have a look please ?
Since I’m just a few timezones away I can’t really compare as I see data in my timezone … not yours


I’m currently showing at 1.23" of rain and a peak rate of 1.22"/hr for yesterday.
After retrieving my CoCoRaHS collection this morning (no additional rain after midnight), I see it collected 1.56" for yesterday, 6/22.
I can confirm that my Ambient Weather WS-5000 reported a peak rate of 3.24"/hr at the time. However, it reported a total of 1.27" for the day, mainly due to the rain coming down so hard it couldn’t catch it all. I observed a lot of “splash out” from its funnel and some overflow since the bottom orifice is a bit too small to empty it fast enough not to over fill the funnel under very heavy rainfall.

Either way, the Tempest was far below actual in its reporting.

It rained here yesterday. Tempest showed .38’ this morning Now reads 0 for yesterday

Mine seems to be calibrating as well. Almost an inch dumped and it says .57

I know in the FAQs (or somewhere) it says that light rains may not get registered, but it’s really rained here (near Portland, OR) and my Tempest has never recorded any rain. Except 2 or 3 times when it didn’t rain at all! And that nightly “rain check” I’ve heard folks talk about…bah, doesn’t seem to help my recordings even though I have the feature enabled. Frankly I’m very underwhelmed at the moment.

Sensor status says OK so the Tempest isn’t detecting a fault. Can you tap on the mount or the Tempest to make it think it is raining? I see that the only rain showing is from June 27 and the station near you didn’t register any rain on that day.

I just tapped on the mount to make the rain notification occur. The station near me…not sure I’d trust that…it never shows any wind either and this time of year it is windy every single evening. :slight_smile:


Lately I’ve noticed that my tempest has stopped notifying me to a rain occuring. Typically this happens when rain is not an outright downpour but on a lighter side. This seem to coat the top of my tempest in water and then it just stops detecting any rain even if its intensity increases.

Has anyone tried applying rain-x on the top of their station to prevent beeding from accumulating and impairing the sensor?

Raincheck is enabled but I’m yet to see it make an adjustment that is accurate. I’m leaving it on for now hoping it’ll improve as more stations around me come online though.

I assume it gave a rain notification. The station near you has a wind and UV sensor failure which the owner should contact WF support about. I’ve had a similar issue with one of my first generation systems and the rain sensor was just fine, otherwise I wouldn’t have used it to compare to rain on yours.

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I have put a ceramic nano-coating on a SKY unit during testing of coatings for the wind gap. It is basically Rain-X on steroids. It had no noticeable effect on rain detection.

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Today was the first time my Tempest OVER REPORTED rainfall. My CoCoRaHas gauge had 0.17” & the Tempest shows 0.34”. It appears we had a strong outflow boundary pass thru around 3 AM, followed by heavy rain. Just an observation.