TfL's "cold weather plans" have been put in place to deal with the snow and ice. TfL say: "Stocks of specialist de-icing fluids have been topped up and, if required, arrangements are in place for trains to run overnight across the various networks.
Additional engineering staff will also be on standby to respond swiftly to any incidents that occur during the cold weather."
As usual, check their website to see what's happening on your lines. There's more snow forecast over the next couple of days, so keep safe on the pavements and roads - it's slippy out there!