In south Wales, the Midlands, East Anglia and southern England, early mist and fog could linger for a while in a few locations on Sunday.
However, once this clears sunny spells are expected.
More cloud will develop in north Wales and northern England with the chance of a few spots of rain.
Northern Ireland will be even cloudier, with some outbreaks of mainly light rain and drizzle.
The wettest weather will be found across Scotland with heavy rain likely in the west, accompanied by wind gusts of 40mph or more in the far north-west.
Temperatures will generally be a few degrees above the seasonal norm and could possibly reach 23C in the sunniest parts of southern England.