Five British airports reopened Thursday after workers cleared runways of the snow that had fallen up to 6 inches (15 centimeters) deep in places.
Stansted, Bristol, Birmingham, Luton, and Cardiff airports had all reopened by midday. Heathrow airport, Europe's largest, remained open but reported 90 cancellations.
Hundreds of other flights were canceled throughout the country. National Rail said it was experiencing disruptions across its network, while the Highways Agency warned against all but essential travel.
Subway services in London were canceled or delayed throughout the morning after the capital got an inch (2.5 centimeters of snow).
The cold snap interrupted what had otherwise been an exceptionally warm winter. January was the Britain's mildest month in more than 90 years, while last autumn was the country's hottest on record, reports AP.
"It's been unseasonably mild, ridiculously mild really," British weather office spokesman Wayne Elliott said. "We were due for some colder weather."
Hundreds of schools closed, including some 600 in Wales, officials reported.