Minimum of 14.7C last night, warmest of the year so far.
Already 19.3C at 09:00 BST.

So warm pools of surface water forming now, even well out to sea.

E.g.

Sevenstones yesterday:-

14:00 - 60.6
15:00 - 61.0
16:00 - 61.3
17:00 - 61.2
18:00 - 60.1
19:00 - 61.2

It's surprising how much it fluctuates. It fell from 60.4F at 2300z last
night to 57.2F at 0300z this morning. Back up to 58.5F at 0700z.

Norman.
(delete "thisbit" twice to e-mail)
--
Norman Lynagh Weather Consultancy
Chalfont St Giles 85m a.s.l.
England

Yes, it is unusual. I think it's been so calm that pools of warm water
form, even well out to sea.

However, it looks like the main causes are the strong tidal current
off Land's End.

There was a very sudden drop in temperature around midnight,
coinciding with the tide changing, and a similar drop at mid-day
yesterday (the previous high tide). It then rose quite sharply after
low water this morning.

Graham
Penzance