The far SW was notably cool last year, when the SST was rather low in
July/Aug. This year the SST in the SW approaches was normal most of
July, though rather below in the last week. It's currently a near
normal 17Cish at Sevenstones, but should rise now with quieter
conditions and more sunshine. Normal summer 'cold pool' near Isle of
White / East Devon.

Interesting is this cold pool which usually appears from mid-July onwards
and stretches from East Devon to the Isle of Wight.

As far as I can tell it stays way off-shore and maybe doesn't even affect
Lyme Bay where the temperatures have been around 17°C to 18°C, even during
the recent unsettled spell, whilst the 'cold' pool of water is currently
being shown as 16°C or so.

http://www.wetterzentrale.de/topkarten/fsfaxsem.html

I would expect the difference to increase, off-shore SST in Lyme Bay
normally reach 21°C to 22°C during fine weather in August and early
September whilst the cold pool shown remains around 16°C to 17°C.

I recall reading a book about sailing and it mentions that between Start
Point and the Isle of Wight there is a slack zone of current caused from the
encroaching Atlantic current coming up against the current from the North
Sea. Maybe there is a slight upwelling of deeper water in that area?
________________
Nick.
Otter Valley, Devon
83 m amsl
http://www.ottervalley.co.uk