Hello Bob, I found the same information (in answer to my Q3) and I've used that. The HP1000 (and clones) provide different information in various records: form the NOWRECORD (the current observation data) it provides the UVI directly, but the HISTORY_DATA record has the UV value but in uW/cm^2. As you say, dividing by250 seems to give a value that is (roughly) in line with what the NOWRECORD provides.
I'd still like information on my other 2 questions but I've assumed for now that weeWx only stores UVI. Susan On Thursday, August 3, 2017 at 1:26:50 PM UTC+10, dr__bob wrote: > > Hi Susan, according to Wikipedia ( > https://en.wikipedia.org/wiki/Ultraviolet_index), it looks like the UVI > is the weighted UV radiation divided by 25 mW/m2 which would be, in terms > of uW/cm2 , "divide by 250", I think. This should yield a number between > 0 and roughly 12. Does it? > > Bob > >