Wind and rain is set to delay Wednesday's travel, with parts of the UK covered by weather warnings.
Overnight showers carrying into Wednesday morning threaten commuters, as flooding is expected and severe gales could affect trains.
The Met Office has issued yellow warnings - which advise people to 'be aware' - of wind and rain affecting southern England and Wales, with the rain warning stretching to the Midlands and Yorkshire.
Persistent rainfall is expected overnight and into tomorrow, easing in the afternoon, with some light sleet and snow in places.
Widespread gales are also expected to develop in the south, bringing gusts of up to 70mph on the coast and 50-60 mph to inland areas.
Rail operators warned of potential disruption to services, while Met Office forecaster Rebecca Simpson said road users should "be aware and be careful".
She added: "There are two warnings: the wind warning and the rain warning. The wind warning is just for the south-west of England and southern Wales, coastal 70mph gusts so fairly windy.
"We are looking at quite heavy rain in the early hours and through the first part of the day. There is the chance with the heavy rain that we might see surface water flooding - if people are out driving they might want to go a bit slower.
"There is a chance of some hill snow around, possibly some sleet at lower levels but it's not going to settle."
South West Trains advised customers to check before travelling, as high winds of up to 60mph and gusts of 70mph are expected on its routes.
A spokesman said it would affect coastal areas particularly Southampton, Weymouth, Salisbury and Exeter St Davids.
The spokesman added: "Trains may have to travel at lower speeds as a safety precaution which may add delays to some journeys.
"To keep you moving safely around our network, some train services may also need to be changed due to possible flooding or debris blowing onto the track."
The weather will slowly ease in the afternoon moving east where there will be patches of rain.
Other rail operators have not put any warnings in place, with Virgin Trains, Southern Railway and Gatwick Express not expecting any disruption.
A spokesman for Network Rail said: "We are closely monitoring the weather conditions and advise passengers to check before they travel."
London Midland said it will issue passenger advice if necessary.