hello you will understand its not a dedicated UV sensor its a light sensor component and i guess a formula is at work to determine the output value hence the decimal place..
many months ago I came up with simple formula to calculate an average UV index figure for a 10-15 minute period by just using a dedicated Solar Sensor from Davis. the formula simply takes into consideration latitude and a simple additional divider. [sol0rad-avg10:--]/$lat/5 or [sol0rad-avg15:--]/$lat/5
basically simply only adjust the last value in this case 5 is to get an average UV value for UK users the value is increased further north you go but only in small increments of 1 decimal place..
basically adjust the last value to get an average example istanbul would be [sol0rad-avg15:--]/$lat/3.45
so i use it now my solar value under cloudy conditions right now is 311 actual UV calculated is 2.15 or rounded down to 2
it was always within expected .it was primarily worked out for those that couldnt justify the £400 price tag of the davis uv sensor at the time.
beta sure is but over 1000 units in circulation doesnt do it justice.. another topic for another day ..take care brian..