An upcoming 1000-mile-wide cold front will bring signs of freezing, according to weather experts.
This could mean the coldest start to May in 25 years.
The upcoming cool season is expected to hit the South with widespread frost and the north with snow and cold showers.
In the south the night can reach -2C while the northern area can drop to -5C.
Nights in Stockholm, Sweden are 3 degrees Celsius warmer than those in the UK are predicted to come.
Forecasters have warned that the weather is “going in reverse”, despite the Easter sun with a 23°C heatwave.
Temperatures below 1.8 degrees Celsius at Heathrow Airport will be the coldest night since 1997, according to the Met Office, Sun Online reported.
This seven-day cold front will last through the holiday weekend of May (May 2).
John Hammond, former BBC and Met Office forecaster said: “Mercury will go in reverse, with a trend towards colder end of April.
“Bloods of fresh air in the Arctic mean there’s a good chance, even across southern England, temperatures will drop to close to or below freezing.
“One or two showers cannot be ruled out over the weekend, most likely over higher ground in the North.”
Some warmer days could rescue Britons from sub-zero temperatures, with a peak of 17C in London.