"Graham Easterling" wrote in message
s.com...


Just checked Camborne (where it's very hazy indeed, bright rather than
sunny a lot of the time) and it's 6.

I think it's partly the change of air mass, but also I've noticed
(mainly from practical experience!) that thin layers of low cloud, or
patchy sea mist which let the sun through, seem to enhance the UV
intensity. (Can anyone confirm this?).

I did hear once that thin cloud can cause a kind of 'lensing'
effect wherby UV rays are effectively magnified.
However this seems rather fanciful to be honest so I don't
really know what the answer is.
--
Col

Bolton, Lancashire
160m asl