Parts of the country have seen more than four inches of snow, with warnings of ice and disruption to transport.
Most areas from Scotland down through to south-east England were hit with a covering of at least two inches of snow and the worst affected areas, including north England and the Midlands, could have twice that. More than four inches has already settled in High Wycombe according to reports, weather experts said.
Nick Prebble, a forecaster for MeteoGroup, the weather division of the Press Association, said: "There has been quite a lot of snow overnight, the worst affected areas are northern England down through to the Midlands and towards the south-east, and of course Scotland.
"Everywhere will see a covering, with most places seeing between one and two inches, but it won't be surprise if some areas get more than four inches. There are reports of nearly four and a half inches in High Wycombe, and even up to an inch in London.
"The snow will linger in the early morning before slowly easing and being replaced by rain in many places. The snow will thaw quickly so shouldn't cause much disruption."
He added that only areas to escape the snow would be west Wales and south-west England. Temperatures are expected to remain cold, hovering a few degrees above freezing point. More light flurries are predicted for Tuesday, with heavier snowfalls due on Wednesday before the weather begins to settle.
The Met Office has issued yellow weather warnings affecting much of England, Scotland and Wales, because of the danger of ice following the snow. It said: "Icy stretches are expected to form on untreated surfaces overnight and into Monday morning. The public should be aware of possible travel disruption."
Across the Midlands, about a dozen schools were closed by the wintry weather.
The Environment Agency has more than 100 flood alerts in place, covering large parts of central and south England. Twenty-three more serious flood warnings have been issued in parts of the south-west and the Midlands. However, the agency said on its website that the forecast risk of flooding across England and Wales is "very low".
The heavy and persistent rain which preceded the snow also caused rivers to "react very quickly" said Dave Throup, Environment Agency Manager for Herefordshire and Worcestershire. Although rivers would be higher, they were not yet anywhere near the disruptive levels reached over Christmas and New Year period, he said.