Big difference at 09:00 between Culdrose (-1.0C) and Penzance (+5.0C, a lot warmer than yesterday's icy start!)

I think the difference is due to the NE wind affecting Culdrose has travelled over land down the Peninsula, whilst the west Penwith (Land's End) peninsula has travelled over the sea. St Ives is even warmer than Penzance around 6C at the same time.

No difference in the forecast temperatures for Culdrose & Penzance, both forecast to be 2C @ 10:00. We often don't get a typical (and normally forecast) diurnal range under these conditions, as the St Ives temperature graph shows.

Graham
Penzance