Snow: Where in the UK will get snow this week?
Dozens of schools in Scotland have already closed due to problems caused by heavy snow - but more warnings of snow and ice have been extended to many parts of the UK over the coming days.
Forecasters say a "major change" is under way as Arctic air sweeps in from the north, bringing snow, ice and plunging temperatures for many.
This could lead to "difficult travel conditions" in some parts, the Met Office has said, and may also disrupt travel and other day-to-day activities.
BBC Weather's Simon King tells us what we can expect to see during the rest of this week.