It was 21 degrees today (with a very high pollen count) and will be noticeably hotter tomorrow, dipping a little on Tuesday before reaching 25 degrees on Wednesday and 24 degrees on Thursday.
To put that in context holiday resort Lanzarote was just 21 degrees today - and cloudy.
By contrast Londoners will swelter in 28-degree temperaures tomorrow, setting a pattern that will continue until Friday.