Britain's May bank holiday temperatures are lower than Moscow's with Monday set to be the coldest May 6 for 178 years.
A 2,000 mile wide North Pole chill is bringing -6C, snow and widespread frosts - and 50mph storms will follow.
Meanwhile in the Russian capital, 20C is forecast today with 11C at night.
The Met Office forecast highs of 14-15C daily over the bank holiday weekend, with beaches deserted just two weeks after being packed in 25C Easter heat.
Bank Holiday Monday will verge on the coldest ever, some forecasters say.
A 'polar plunge' - shown on a dramatic weather map - is sweeping through Europe all the way to Africa.
UK Weather: SNOW to hit as temperatures plunge below zero over bank holiday
Met Office forecaster Steven Keates said: "Cold air from well north of the Arctic Circle, not too far from the Pole, is flooding to the UK and a good part of Europe as far south as Italy.
"-5C could be seen on Sunday morning in the north west, and slightly lower is quite possible on Monday morning in the west.
"Beating the -5.9C early May Bank Holiday Monday UK minimum temperature record can't be ruled out."
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The Weather Outlook forecaster Brian Gaze said: "Bank Holiday weekend BBQs are on ice as date temperature records are challenged.
"A polar plunge is bringing one of the coldest early May Bank Holiday weekends the UK has ever had."
"There are more people in the cinema than on the beach," Bournemouth Accommodation and Hotel Association's Andrew Woodland added.
The Met Office predicted this morning's -5C to push closer to -6C tomorrow morning and the west will be the coldest.
Tomorrow will be the coldest May 6 since records began 178 years ago in 1841 if it is colder than the -5.6C in 1980 at Camps Reservoir, South Lanarkshire, Scotland.
Tomorrow could also be the coldest ever early May Bank Holiday day.
The day's coldest UK peak temperature is 14.5C in 1982, BBC weatherman Simon King said.
Britain is 15C colder than a year ago, when the early May Bank Holiday saw a record 28.7C at Northolt, London.
Today and tomorrow will be mainly dry - but 50mph gales in the south follow from Wednesday.
Met Office forecaster Steven Keates added: "Windchill made Saturday feel not much more than freezing in the north east, with maximum temperatures of 14C or 15C at best until after Monday.
"Frosts will be widespread, and Saturday had snow likely on Scottish mountains and possible on higher parts of the Pennines and north Wales.
"Sunday and Monday will be drier, but with cloud and some bright spells.
"It's a massive contrast to last year's record early May Bank Holiday highs.
"And it turns much more unsettled from Wednesday with the risk of gales and 40-50mph gusts in the south and showers or longer spells of rain."
