Racegoers should wrap up warmly and bring an umbrella today as thousands flock to Aintree for the 165th John Smith's Grand National.
A northerly breeze will keep the air icy cold as 40 runners and riders compete in the world's most famous steeplechase.
Racing enthusiasts should also prepare for rain, forecasters warned.
"It will be pretty chilly at the Grand National today, reaching about 9C. There will be showers this afternoon with hail mixed in," Paul Mott, forecaster at MeteoGroup, the weather division of the Press Association, said.
The rest of the country will not fare much better as the South West faces heavy showers.
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Mr Mott said: "There will probably be some thunder and hail mixed in and there will be heavy showers in the North East too. There could be some snow on the Pennines first thing in the morning, leaving a slight covering on the hills, but that should melt by 8am.
"Last night there was light snow over Aberdeenshire and the Highlands leaving maybe a centimetre or two on the ground.
"Tonight will be cold and dry, reaching -4C in rural parts of Scotland. It will be zero degrees in the south east and quite a sharp frost will be enough to kill off any flowering plants."
Mr Mott said Sunday night would be even colder.
"It will be about -4 to -5C in rural parts of south east England, which is very cold for this time of year."Check out these fillies at Ladies' Day