More than 100 flood warnings are in place across England as travellers face major disruption in their bid for a Christmas getaway.
There is a severe weather warning for more heavy rain in place across the South for most of the weekend, lasting the whole way up until noon on Sunday.
Up to 30mm (1.18in) of rain is forecast in parts, prompting the Environment Agency to issue 101 flood warnings, where flooding is expected, and 256 flood alerts, which warn flooding is possible.
Impact on transport will be of serious concern for those heading away for the festive season, with more delays anticipated on the roads and trouble also possible for people travelling by air and rail.
Flight cancellations are threatened in Northern Ireland, with a warning of freezing fog.
John Halsall, managing director of Network Rail's southern region, the network "under enormous pressure" because of the torrential rain, with Southern, Thameslink and Gatwick Express all affected by flooded lines.
People are being advised to check timetables before they travel.
As for the roads, motorists heading to the port at Dover have been facing huge delays after the eastbound carriageway of the M20 in Kent was closed at the junction with the M25 following a serious traffic accident.
It comes after a section of the M23 between London and Brighton was closed on Friday after a river burst its banks and flooded the carriageway.
Sussex Police have described driving conditions in the region as "miserable" and warned drivers there was "a lot of standing water on the roads".
Devon and Cornwall Police said flooding across the counties made "a number of roads impassable" - and it urged drivers to take extra care and avoid driving into standing water.
Highways England has urged motorists to adapt their driving for the wet weather by slowing down, keeping well back from the vehicle in front and easing off the accelerator if steering becomes unresponsive.
The Environment Agency also warned of trying to drive through floodwater as only 30cm of water can move a car.