Britain is set to enjoy the hottest day of the year so far, with temperatures expected to soar to 27C (80.6F) this week.
Many parts of the UK will see warm sunshine and clear skies over the next few days as temperatures climb into the mid-20s.
On Wednesday, the temperature in London and the South East could surpass the 26C (78.8F) recorded in Treknow, Cornwall, on Good Friday.
Some regions will be warmer than some of Europe's top holiday destinations, including Marbella and Ibiza, the Met Office predicts.
The mini heatwave will continue into Friday for some, testing the nation's resolve as people are still being urged to avoid crowded outdoor spaces.
After the prime minister announced the loosening of some of the lockdown restrictions in England last week, sunbathing and picnics are now allowed in parks - as long as the two-metre social distancing rule is observed.
Here is what you're allowed to do in England:
Wales, Scotland and Northern Ireland still have strict lockdown rules after the devolved leaders criticised Mr Johnson's "stay alert" slogan, saying theirs is still "stay home".
On Sunday, a family from Birmingham was fined and sent home after police carrying out road checks in Wales saw them walking down Pen y Fan on a closed footpath in the Brecon Beacons.
Despite the rules in England being eased slightly, gatherings of more than two people from different households are still not allowed.
A 70-person "rave" with a DJ in Granville Country Park in Shropshire was shut down by police on Saturday evening but they were not fined as officers said they were not breaking any other rules.
Higher fines in England were introduced last Wednesday - £100 for breaking the rules, rising to a maximum of £3,200 for repeat offences.
Met Office meteorologist Matthew Box said there will be a "north-south divide" on Monday and Tuesday, with spells of rain in northwestern parts of the UK while southern areas will reach highs of 24C (75.2F).
But it will begin to clear going into the middle of the week, as warm southerly winds from the Mediterranean start to move north.
By Wednesday, parts of Scotland and Northern Ireland will reach highs of 22C (71.6F), while Wales could see 23C (73.4F) by the afternoon. The North of England will hit a maximum temperature of 26C (78.8F).
Mr Box said: "It's going to be very hot for large parts of England for most of the week, reaching highs of 27C (80.6F) on Wednesday, which would make it the hottest day of the year so far.
"This will occur due to large areas of high pressure, combined with southerly winds from the continent, bringing with it, pleasant sunshine, dry skies and warmer air."
On Thursday, there is a possibility of thunder and rainfall across the south and east of England and Wales, while Friday could be windy, mainly for western areas, with heavy downpours.