There's a link at the start of this thread; this is the reading for Reading- the resolution of reliable recording stations isn't as dense as for usual met. data (temperature etc). We here in the Itchen Valley are some way south of Reading, and Portsmouth is even further south, but more significantly, coastal; also at lower altitude so the level will be affected both ways, I suggest, but in general I would expect Portsmouth to have a higher UV (slightly) if conditions are similar.
Originally Posted by: Bertwhistle