Met Office meteorologist Kathryn Chalk said in a forecast on YouTube: "After an unsettled Sunday, most of us should see a good deal of sunny spells as we go through Monday but we still hold on to some heavy spells of rain so it is still a damp start so take care during rush hour there could be some spray on the road.
Sarah Cook, flood duty manager at the Environment Agency, also said heavy and persistent rain had brought “a risk of significant inland flooding in parts of south and mid Wales”.
A MET Office map has revealed how a huge band of wet weather will bring a month's worth of rain in just hours.
Ms Cook said: “Impacts could include river flooding and surface water flooding from urban watercourses, drains and channels.
As the rain sweeps across the country, some areas will also see hailstorms and blistering winds.
