Parts of the south and east officially entered a heatwave on Monday, after three days at or above their threshold temperatures.
Heatwave criteria were met more widely on Tuesday as temperatures peaked at 32.4C in both Teddington, Richmond upon Thames, and also in Frittenden, Kent.
More locations could reach 34C or 35C in the coming days, with the hot spot likely to be in southern England.
Heat will continue to build and extend north and west into Northern Ireland and Scotland until Friday. Here the peak is expected in the high 20s Celsius.
As high pressure shifts towards the end of the week, an easterly wind will pick up and cool down eastern areas of the UK.
The focus of the heat will then be further west, across central southern England in particular. South Wales could also see highs of 33C on Friday.
