I'm building my own station and just setup an UV sensor (VEML6075).
The sensor seems to give a bit too high value, ex today max was 6, while I found 3 to 5 on a few website.
I want to add a calibration ratio to improve my measurement.
But here is the point, I found ~3.7 to 5 on website!!!, that would make a different ratio.
Here are the examples:
https://www.wofrance.fr/France/Toulouse/IndexUV.htm (give 5 for today)
http://sunburnmap.com/ (give 4 for today)
temis.nl/uvradiation/nrt/uvindex.php gives 3.7 for today at my location.
How would you proceed ? is there a know good reference site for this?