The cold snap is expected to "go out with a bang" on Friday, with the Met Office issuing amber warnings for the East of England.
Up to six inches could fall in northern England, four inches in the Midlands and up to two inches in the South.
The Met Office said it has amber warnings in place for much of Scotland, the north of England, east of England and East and West Midlands, with yellow warnings in Wales, south west England and London and the South East.
The RSPB is urging people to help birds this winter by putting out food and fresh water.
Feeding wild birds throughout winter is vital, but one Norfolk wildlife reserve owner has gone further by hand-feeding a tiny robin.
The MP for Colchester Sir Bob Russell has questioned widespread school closures because of the snow.