Reactions to CL system for UV explained

Today a peak of UV 3.
Normally it should be a maximum of 1 to 1.5

Could it be reflectation of clouds? :slightly_smiling_face:

The comming days are going to be quiet cloudy, so I’m gonna check the Sky daily for UV readings.

The days before the UV readings where perfect.

Hi @poider1982 . Thanks for the report, we really appreciate it. The CL system for UV is in it’s early days and can certainly benefit from input from the field. We took a look at your data. The CL system benchmarked a reference UVI value of 1.6 on Oct 20th which helped calibrate your sensors over the last couple days. We’re not sure what happened today. Let us know what the next few days report. Thanks!


I’ll keep You up to date.
Furthermore a big thumbs up for Weatherflow.
UV readings and especially air pressure doing great now.
Also Lightning detection works perfect.
Never had any false strikes.

Oké it’s going off topic, but all the efforts of Weatherflow deserves a big compliment. :ok_hand:



My UV readings are approximately half of what they should be. Currently my Sky is reading 4.4. The forecast for today suggests the UV should above 8. The sky is clear and I have rest the device to ensure all updates are active.

Any suggestions about why the reading is so far off?

Without knowing your station ID, location and how your Sky is mounted it’s impossible to say.

Sorry Gary,

Station ID: 4581

A clear view of the Sky in all directions.



Hi Geoff. We just took a look at the CL analysis for your SKY and it doesn’t have enough data to confidently suggest a change in calibration. However, a manual inspection reveals that it’s indeed off by a factor of about 2.1. We’ll apply that adjustment today and the CL system will update it over time as more data is collected.

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Thanks David,

As you would expect, today has been overcast. However, as the UV levels recorded today are about the same as those recorded yesterday in full sun, it looks hopeful.

Out of interest, how many days worth of data is required to make an adjustment?

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We need at least 4 days of clear days, but that’s just one condition that must be met so it can often take more.

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