A yellow alert for rain covering areas of Dorset and Devon is in place until 9am on Saturday, with forecasters warning a spell of heavy rainfall could affect travel and create possible flooding.
Yellow alerts for rain and wind have also been issued for southern Scotland and Northern Ireland.
A separate wind alert covering parts of Wales, the Midlands and northern England comes into force at 9am on Saturday.
Much of Ireland is also under wind warnings on Saturday with Met Eireann cautioning severe gusts could cause disruption and travel difficulties.
Areas with Irish Sea coasts could see gusts of up to 70mph, with parts of the Midlands, northern England and Northern Ireland experiencing wind speeds of between 45 and 55mph, the Met Office said.
Wind speeds will increase in the west during Saturday morning then across other areas through the afternoon, before easing slowly from the west through the evening.
Homes and businesses may experience flooding as up to 80mm of rain falls in some parts of the UK, the forecaster said.
Met Office spokesman Stephen Dixon said a band of heavy wind and rain will move from the south-west of the UK towards the north-east on Saturday, “bringing with it heavy rain for much of the country”.
He said: “By the afternoon most of the heavy wind and rain will have passed and it will just be showers for southern areas.
“We will also be seeing some quite strong winds in Wales, the Midlands, northern England and Northern Ireland, particularly coastal communities around the Irish Sea.
“We’re in for a wet and windy weekend.”
The bad weather could cause delays to road, rail, air and ferry transport, and coastal routes, sea fronts and coastal communities may be affected by spray and large waves, the forecaster said.
The unsettled weather will continue into Sunday and next week, with a chance of further weather warnings.
Mr Dixon continued: “There is another area of low pressure coming on Sunday with the possibility of further warnings being issued.”