Saturday
A weak ridge of high pressure affects the southern part of the UK on Saturday as a warm front moves into Ireland and Scotland. Broken cloud in northern Scotland to start, but some bright spells here. Sunny spells for much of England and Wales, although cloud increasing in Ireland bringing outbreaks of light rain. This rain then spreads into western Scotland through the late morning and across mainland Scotland through the afternoon with some drizzle over the hills of northern England. Isolated showers in southern England. Dry elsewhere with the best sunshine in the east and south. Highs near 22C in the sunshine in the southeast. More generally 15 to 19C, but just 9 to 10C in northern Scotland.

Saturday Night
Rain continuing over much of Scotland, Northern Ireland and northwestern Ireland through the night, becoming heavier towards the morning. A cloudy but dry night for southeastern Ireland, Wales and western England, clearer skies to the east. Overnight lows falling to 5 to 8C over northern Scotland, staying in double digits elsewhere at 10 to 13C.
 

Sunday
Low pressure crosses Scotland on Sunday. This takes fronts with it, bringing some heavy periods of rain to much of Scotland and northwest England. A more showery band of rain passing eastwards over the rest of northern England and Wales, into the Midlands and southern England in the afternoon. Brighter weather with scattered showers follow to the west. Temperatures at a cold 8 to 10C in northern Scotland, 12 to 18C in central and western parts, but up to 21C in southeastern England.

Monday
Low pressure dominates into Monday with fronts pushing south. The fronts give showers, some heavy especially in northern England, Wales and Ireland. Showers may merge into more persistent rain across Scotland with the risk of some wintry conditions over the highest peaks of the Scottish mountains. Breezy and cold at 9 to 10C in northeast Scotland, more widely at 11 to 15C, milder in the southeast of England at 17 to 19C.