Rain calibration corrections

It seems my Sky reports now about 1.2 too much rain it was factor 2.7 too much seems to be improved. Are callibrations done??

Hmm not yet i read elsewhere, strange🤔

When light winds and rain (windspeed 16kph or less) I get very good correlation between my Davis Vantage Vue and Weatherflow. Higher winds and the discrepancy seems to get worse (up to 3 times the Davis reading).

Does the haptic rain sensor take into account the wind speed when measuring rainfall? Light rain has a very low terminal velocity hence less effect on the haptic sensor. Wind will increase the apparent effect of the rainfall won’t it?

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Thanks for the report!

Not yet, but it most likely plays a significant role. We’re still evaluating how to best account for that variable (and others).

Overall, yes, although the effect is complicated. Wind changes the angle of attack, which tends to spread out the drop impact over the cap. This reduces the amplitude of the impulse but the total energy transferred is the same. Wind also causes more drops to impact the sides of the SKY which tends to add to the signal as well. We’re still working out the relationship between wind and rain, but we’re making progress!

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My Sky station seems to be off by -0.3 compared to stations around me (non-weather flow stations). Just wondered if this was an issue or if my unit was bad. I have a clear view of the sky with no obstructions around the unit. Any thoughts? 58%20AM

There are several topics on this subject. Here is one: Rain Gauge Reading Seem Off (auto-calibration system not yet deployed)

Thank you! I’ll check it out.

I guess there no ETA on when these updates will take place? Just wondering if I should send it back if it’s going to be six months out.

Was any of the perception snow or ice?

Also, your station is been online for only three days. Even if the auto calibration was 100% working, it will take time and data for the system to calibrate properly. I suggest you wait it out and enjoy the data you will be receiving. Eventually you will see that you have great data at an even greater price point.

It was all rain. But I’ll wait it out. Thanks, Gary!

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45am During field testing found 2 very different wind readings
on Sky A and Sky B suggesting some water from night’s rain may
be impacting one as there have been no gusts close to 38mph as reported here.!
Hope this helps in future development of superhydrophobic surface.

45am|375x500
by 45am

it is known that a water drop on the sensor does affect the readings.
As david @dsj mentioned on several occasion in this forum, the calibration that will help some and a special coating are evaluated to help solve this and many other problems regarding rain/wind events.
But none have been released yet, so be patient :neutral_face:

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So I’m seeing the rain sensor is not sensitive enough to get light drizzle… it’s been like this all morning and not a single measurement on the station, the ground, leaves, concrete is all wet but no rain recorded…

I’ve posted a video in the WeatherFlow Facebook group
Private link removed.

There are several topics here discussing that. Search for “drizzle” or views posts with the “drizzle” tag.

I’ll say this, last night we had wind gusts to 30 mph and a few minutes of torrential rain. Sky measured 0.17 inches when all was said and done. I was pleasantly surprised/shocked that my CoCoRaHS gauge had EXACTLY 0.17 inches of rain in it.

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station 4664
Hi when we have light to moderate rain sky measures 4-5 times what the actual rain gauge measures
e.g today so far we have had .3mm but sky measured 1.4mm. this has been pretty much the same all the time, however when we get rain moderate to very heavy the readings are within points of a mm
regards

It is a great feeling when they agree. I think we all walk out there with hopes
of 0.01 or less disagreement. Enjoy your correlation success.

Hi Guys,

Since moving house and installing the station, rain does not appear to be recording as it was in the past. My installation is more in the open and I’m in an area that has more rainfall so I’d expect more accurate readings. In fact from about 30th Dec there has been very little or no rain recorded.

Station ID 2434.

What can I do from my side?

Regards,
Gordon

Okay, something has changed since my earlier post. There was some rain but tapering off… It’s still very windy and not rain, yet rain is showing as ‘heavy’.

My SKY precipitation readings have been consistently reporting less than my Stratus rain gauge. Although the readings are better now than they have been since I got the station, they are still significantly off. For example, yesterday’s storm in Cypress, CA recorded 0.51" on the SKY and 0.76" on the Stratus rain gauge.

Mine performed like this when I had Sky mounted on a 10’ steel pipe.
I noticed at 25mph or higher Sky would sway just a little but it caused vibrations
which were recorded as precipitation. I’ve since mounted Sky on a 4x6" treated
beam and have not had any instances of false precip recordings. Just my experience but
it may apply to others