The previous coldest Easter day since modern records began in 1960 was Easter Monday in 1986, which dipped to - 9.8C, the Met Office said.
Average temperatures for this time of year are between 10C and 13C.
The prolonged cold spell covering the UK could last until mid-April, the BBC quoted forecasters as saying.
Easter itself is a moveable celebration which falls on the Sunday after the spring full moon, and can fall anywhere between 22 March and 25 April.
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The Easter record comes after the entire month of March was provisionally declared the coldest since 1962 in the UK.
The Met Office said that from March 1 to 26, the UK mean temperature was 2.5C, which is three degrees below the long- term average.
The unseasonably wintry weather has caused problems in parts of the UK, including with electricity, farming and agriculture, and the road network, the report said.