Heavy rain and high winds will create difficult driving conditions for those trudging home from bank holiday getaways.
A band of wet weather will sweep south eastwards across the UK on Monday, but the end of the unsettled spell is in sight.
Temperatures will be above normal for this time of year by the end of the week, as drier, brighter weather warms up the country.
Met Office forecaster Steven Keates said: "It's by no means a washout for everyone."
The rain will "lose some of its oomph" as it reaches the southeast in the afternoon and sunshine will emerge either side of the wet front, he said.
Temperatures could reach 17C (63F) in the London area, while in Aberdeen the mercury may hit 15C (59F) on Monday.
But hail and thunder aren't out of the question on the Bank Holiday in northern England where it will be bright sunshine one moment then dark clouds and thunder the next.
High ground in Scotland could experience another flurry of snow despite the warm temperatures, the forecaster added.
Towards the end of the week temperatures will reach up to 16C (61F), according to the Met Office.
Mr Keates said it was an "improving week weather wise".
"At the moment, once tomorrow's rain has passed across the south, the rest of the week does look fairly dry," he added.