According to the 0030 forecast on R4, and the Met Office website,
the max at Gravesend yesterday (Monday) was 22.7°C . It was only
16.2°C here, 17 at Gatwick, 18 at Heathrow and 17 at London City Apt.
(by METARs). It was mostly sunny all day here, and presumably at the
other places so Gravesend's figure is difficult to believe,
particularly as the wind was E'ly. It can't just be a website error
because it was repeated by Nick Miller on R4.

Tudor Hughes, Warlingham, Surrey.