The deluge over the first 11 days of the month threatens to make it the wettest October on record as weathermen said there would be more rain today.
The South has so far recorded 90mm (3.5ins) - almost double the average of 46mm (1.8ins) for the whole month. The record of 143mm (5.63ins) was set in 1987.
There has also been much heavier than average rainfall in eastern Scotland, in South-west England, south-west Wales and the Midlands.
In East Sussex yesterday, firefighters received more than 100 calls as houses were flooded and roads became impassable.
An RAC spokesman said: 'We are issuing a severe weather warning to motorists in the South of England - particularly in Sussex and Kent.'
Flood warnings were also made by the National Rivers Authority southern region, covering parts of the river Uck, the river Ouse, the river Brede, the river Rother and the Medway.
In Suffolk, the fire service was inundated with calls from flooded householders along the east coast and the rain affected at least 20 major routes in the county.
Weathermen said there would be more rain today but by the end of the week it would be replaced by colder, clearer weather.