Slack high pressure influences much of the British Isles bringing a fair day with a good amount of sunshine. Some hazy high cloud. Early low-lying mist patches will soon clear. Small risk of an early shower around southeastern coasts. Winds generally light. Freshening southwesterly winds will affect the far northwest, and western Scotland will see low cloud and patchy drizzly rain coming in from the Atlantic. Starting cool, rising to afternoon highs of 16 to 19C.
A frontal system will move in from the west overnight, with thickening cloud and rain for western Britain and across Ireland, becoming extensive across Wales, the west and southwest of England into the early hours. Some heavy falls developing over western hills. Much of Scotland sees rain before dawn. Eastern England likely to stay dry through the night, with clear spells before high cloud thickens. Blustery around coasts. Low temperatures 7 to 11C, coolest central-eastern areas.
A trough of low pressure and frontal system will move slowly east across Britain affecting most places through the day. Areas of persistent rain, some heavy bursts - a risk thundery downpours forming. Some places across central & southern Britain may see rain last many hours, resulting in cool temperatures, barely above 10C locally. Northwest winds will freshen in western areas. Showery with some brighter spells for Northern Ireland and western Scotland. Highs 13 to 16C.
Pressure will build and previous fronts will break up. A fair day is likely over much of the country with winds fairly light. One or two areas of residual showers left from the remnants of Monday's rain may occur across central & southern Britain, although many places will be dry with sunny spells. Some early low cloud and mist will clear. Toward evening and into the night, renewed rain and strengthening winds moves into the northwest of the British Isles.