By midweek, an area of low pressure over France will bring the UK lighter easterly winds, marking a return to slightly more humid weather.
Temperatures will increase in most areas and are expected to peak on Thursday.
Readings around 26C or 27C are forecast across the western sides of Scotland and Northern Ireland.
More of England and Wales will experience highs around the 30C mark, with some weather models predicting isolated peaks of 34 or 35C.
The UK has already seen a record-breaking nine days this year where temperatures have reached 34C or higher, two more than the previous record years of 1976 and 2020.
Night-time temperatures will also increase again, with the prospect of a few ‘tropical nights’ being recorded, as temperatures hold above 20C.