Parts of Scotland and northern England will start the day with outbreaks of thundery rain before it slowly clears to the northeast through the day.
Sunny spells and a scattering of showers can also be expected in the north later on in the day.
Further south some showers are possible early on across parts of the Midlands and eastern England but there should be plenty of hazy sunshine for the most part.
Meanwhile, it will be a warm and humid start across eastern England, before fresher conditions follow on to all parts by the end of the day.
Top temperature 25 Celsius (77F).