Arctic winds will cause temperatures to plunge back to winter levels on Easter Monday and bring a "significant" wind chill.
Overnight on Sunday, figures could drop as low as -7C (19.4F) in some areas of Scotland, with sub-zero figures also forecast in parts of northern England.
A high of 17C (63F) in southern England on Sunday afternoon will drop to just 6C (42.8F) on Monday morning.
"It’s going to be cold for everybody, but windy too," said Met Office forecaster Sarah Kent.
"The wind chill is going to be significant."
The reason, she added, is "Arctic maritime air".
Three yellow warnings for snow and wind are in place until midnight on Monday for parts of Scotland north of Perth.
As much as 15cm of snow could fall in northern Scotland, while wind speeds may reach 70mph.
Coastal areas of eastern England, parts of Wales and Northern Ireland could also get snow showers on Easter Monday.
While southern England can expect some sunshine, gusts of up to 30mph could make highs of about 7C (44.6F) feel more like minus one, Ms Kent said, adding that those braving the outdoors might need "three jumpers".
"Today is a lovely day for an Easter egg hunt in the back garden, whereas tomorrow if you were doing one you’d probably want to wear three jumpers," Ms Kent said earlier.