Very high rainfall amounts. How to calibrate Sky?

My sky is still reporting extremely high rainfall amounts after being online for a week. Based on rainfall amounts collected by other gauges at the same location it appears to be recording at 5 times the actual amount. For example today’s rain event totaled 0.8" in the other gauges, but over 4" by the Sky.

From the looks of it there is no way to manually adjust it so what is the process to get this fixed?

My station number is 1731 if that is needed.


it would be a nice to have feature for sure where you could have a user selectable calibration value
I think they are working on something along those lines
there is a learning facility, but being able to do your own calibration would be better , in my opinion
the problem likely is that calibration is not likely to be a one factor suits all (for different rain types (light/heavy , with wind, etc)


well said @weather-display

it’s more complicated than just a selectable calibration, because the sensor is more sensitive for small droplet than the classic gauge for the rainfall. as the sensor use a vibration for every small or big droplet that it fall on it, to collect the value of the rainfall, so this become more complicated to do a simple calibration to correct it.

I have the same problem. My Sky shows 6.13" of rain yesterday. Another weather station very close to mine shows 1.35" of rain yesterday. It rained hard yesterday, but it wasn’t >6" of rain. Is this an initial calibration issue that will adjust over time, or is there a problem with my unit?

My station number is 1600 if that is needed.


I have the same concern. We had some heavy showers yesterday and I am showing 21.019 inches in the last 24 hours; .648" in the last hour. Any suggestions?

just a FYI ,3rd party software like weather display does allow you to have a rain offset

My case seems pretty simple. So far every rain event recorded divided by 5 equals the amount collected by non-electronic gauges. If it were a sensitivity issue, the multiplier would not be the same every time. Checked the gauges this evening, and guess what. Sky total divided by 5 = mechanical gauge total. 5 rain events over 9 days, some heavy, some light, some high wind, some calm, all 5X actual measured rainfall.

good that its a factor that is linear
that does make it easier
(e.g you could use a rain offset to compensate for that factor in a 3rd party software for example)
it would be good I think if weather flow could make it where the user could set a offset factor too

Wouldn’t you expect a rain gauge to read accurately and not need an offset?

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but its not your normal rain gauge (e.g tipping spoon)


I have had my Sky running for about a week and suspect that the rainfall measurements are overstated. As I purchased the WeatherFlow system primarily for highly local rainfall data as input for my sprinker system controller, it’s important to be able to trust the measurements.

I decided to open a new topic on this to directly ask WeatherFlow staff to comment (to the extent they can without revealing any IP secrets) on how the calibration process works. If possible could you:

a. describe the general self-calibration process
b. comment on what other sources of rainfall data are used to compare against the Sky data
c. predict what length of time (or number of measurable rain events) are required to achieve a reasonable calibration

Thanks. My intent here is to have an idea of how to proceed to use the data in a reliable way.


I have pretty much the same questions. My SKY shows 2.5" of rain yesterday but my trusty AcuRite shows around 0.6" which agrees with two local Wunderground stations. The SKY has only been in its current location (WeatherMount2 on my roof) for a week, though.

Still have a significant calibration error with mine as well. Records several times the actual rainfall amount over multiple rain events. Not seeing the expected improvement in measured values as expected due to some calibration process that WeatherFlow uses expect perhaps for very light events.

I have merged the topics as multiplying them with the same question over and over won’t advance the subject and it makes reading, following it more difficult (even for WF staff)

OK i will change my words then. Wouldn’t you expect a rain “sensor” to read accurately and not need an offset?

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yes, but, its new technology (at price level etc), the hepatic rain sensor
and is still be refined
and the more data they get, the more it can be refined
they could have spent more time field testing to refine it more, but people were complaining about missed deadlines more and more

but I think we all need to have faith that it can be improved, the algorithms, i.e via firmware updates, over time
keep the reports coming in, it is actually what they need to hear, no matter how hard that might be :wink:


My last two rain events.
.26" actual, Sky .75"
.27" actual, Sky .91"
Second rain event was a much higher rain rate than first.

Same here. Nearest station recorded 1.2". Sky recorded 4.11".

This is ridiculous. Waited for two years for something that needs more calibration? I bet most people would’ve waited longer for a more refined product…

I agree with this…Interesting that no WF staff has commented on this

but the more data they can get, the better the calibration will become
i.e you are all now field testers for the rain data