The Met Office has warned that heavy rain will affect 29 counties on Thursday, all in Scotland and Northern Ireland, as temperatures cool from Wednesday's heatwave.
Heatwave peaks then cools
Temperatures could reach 35C in south-east England on Wednesday, marking the fourth heatwave of the year. However, the heat was less widespread than previous spells, with Scotland, Northern Ireland and northern England seeing highs in the high-teens to low-20s.
On Thursday, conditions will cool across the board. Southern and south-eastern regions may still feel warm in sunshine with mid to high-20s, but most of the country will drop towards seasonal norms.
Heavy rain in the north
Met Office meteorologist Honor Criswick said: "The good news is, if you're not a fan of the heat, that overall temperatures will come down into a slightly cooler day [tomorrow]."
Light showers are possible in parts of England and Wales, while rain could be heavy over northern parts of the UK, particularly Scotland. Criswick added: "Perhaps the odd shower in the south but still very light, and not much rain associated with these at all. Once again most of the showers will come across the north where they could still be heavy - and the odd one or two here or there across England and Wales."
Counties affected
The Met Office forecast maps show heavy showers impacting 29 counties on Thursday, all in Scotland or Northern Ireland.
Scotland: Aberdeenshire, Angus, Argyll, Ayrshire, Banffshire, Buteshire, Caithness, Clackmannanshire, Cromartyshire, Dunbartonshire, Fife, Inverness-shire, Kincardineshire, Kinross-shire, Kirkcudbrightshire, Lanarkshire, Midlothian, Moray, Nairnshire, Peeblesshire, Perthshire, Renfrewshire, Ross-shire, Stirlingshire, Sutherland, West Lothian.
Northern Ireland: Londonderry, Tyrone, Fermanagh.
BBC forecast: thundery showers possible
BBC Weather's forecast suggests some showers over Scotland could turn thundery on Thursday. It states: "Tomorrow, northern areas will have showers, these heavy and thundery across the north of Scotland. Further south, a band of cloud and local drizzle will push south-eastwards, followed by sunshine.
"Sunshine for most in England and Wales Friday, but with some scattered showers across Scotland and Northern Ireland. Sunny spells again for most on Saturday, though Scotland may see isolated showers, mainly across the far north.
"Sunday will be mostly dry and sunny to start but cloud will build in for many later in the day. A few spots of light rain are possible in places."
