Saturday
A murky start, and remaining overcast for many. Rain and drizzle will linger over many hours for Wales and northern England, and this may be thundery for a few hours early morning. Scotland will also see outbreaks of rain, most widespread in the Highlands. Mainly dry for the Midlands and south. Very little wind for many areas, but expect a south-westerly breeze toward the south coast, and a fresh northerly in Scotland and Ireland. Disappointingly cool in rain at 13 to 15C, and struggling around 10C in northern Scotland. Highs reaching 18 to 21C in any sunshine in the south-east.
Saturday night
Cloudy skies for most areas overnight. Patchy light rain and drizzle for southern Scotland, northern England and perhaps the Midlands, but amounting to very little in total. Little wind overall. Overnight temperatures 9 to 13C for England and Wales, although where skies clear in Scotland, it may fall to 6C in the central belt, and locally 1 or 2C in some Highland glens.
Sunday
High pressure builds slowly from the north during Sunday as weak fronts slip southwards across England and Wales. Fairly cloudy overall, with patchy rain and drizzle in the south, although amounts small. Brighter skies should develop across northern Britain and Ireland. Mostly light winds, but a freshening easterly breeze will develop across northern England and the Midlands. Cool in the north at 13 to 15C, but 17 to 20C in the south.
Monday
High pressure resides across the British Isles, bringing widespread dry and fine weather. Light winds overall, but a fresh breeze may affect the south-east of England. A good deal of sunshine, although cloud may be slow to break in southern counties. A chilly start in northern Britain, with a slight frost possible around dawn. Afternoon temperatures reaching 16 to 20C.