The UK will be "much, much, colder" on Friday, forecasters say, as disruption caused by snow continues.
Overnight, temperatures fell as low as -20C in Braemar, Aberdeenshire.
There are severe warnings of heavy snow for parts of central and eastern Scotland, Wales and north-west England.
Gatwick Airport has reopened but delays remain. Southern and Southeastern rail have reduced services, trains in East Yorkshire are cancelled, and there are virtually no services north of Glasgow.