The UK has enjoyed record-breaking spring sunshine, with a high of 28.7C recorded at RAF Northholt in west London by the Met Office.
It marks the hottest day over the Early May Bank Holiday weekend since the holiday was introduced in 1978.
South-east England, the Midlands and East Anglia were the warmest spots.
The Met Office's Charlie Powell said temperatures in the high 20s were "the exception rather than the rule" for the UK as a whole.
The Met Office said Scotland and Wales just missed out on breaking their own bank holiday weekend records but still enjoyed their hottest day of the year so far with 23.1C recorded at Charterhall, Berwickshire, and 25.7C at Usk.
The 23.6C record for the Early May Bank Holiday Monday - set in 1999 - was broken when Herstmonceux in East Sussex reached 24.2C.
The previous record for an overall Early May Bank Holiday temperature was set in 1995, when 28.6C was recorded on the Saturday of the long weekend.
The average high for the Early May Bank Holiday in London is about 18C.
The high in Belfast on Monday was 19.5C, while Cambridge, Rochdale and Sheffield all saw temperatures of about 26C.
But not every area enjoyed blue skies and high temperatures, with the northern coast of Devon and Cornwall seeing low cloud, mist and sea fog and a high of only 11C at some locations, including Polzeath.
Bank Holiday Monday temperatures around the UK
Northolt - 28.7C
Sheffield - 26.9C
Cambridge - 26C
Rochdale - 25.9C
Cardiff - 25.5C
Edinburgh - 21.4C
Plymouth - 21.2C
Belfast - 19.5C
Aberystwyth - 16.1C
Bude - 11.7C
Much of the UK has seen blue skies and sunshine across the three-day holiday weekend, leading to busy roads and overcrowded trains as people flock to the coast.
Temperatures peaked on Sunday at 26C in Northolt.
How to stay safe in the sun
According to Dr Farrah Sheikh, absorbing enough sun is important, as it provides essential Vitamin D. However, it is also important that we are sun safe. She suggests the following:
- Stay out of the sun when it is at its hottest (between 11:00 and 15:00 BST)
- Try to cover up as much as possible - wear a hat
- Apply plenty of sunscreen, particularly with children as their skin is a lot more sensitive. Re-apply sunscreen every one to two hours
- Drink lots of fluids
How to keep your pet safe
Vet Dr Simon Constable says sun safety is as important for pets, and suggests the following key pointers:
- Use non-toxic pet sunscreen, particularly on pale-coloured pets, such as horses and dogs
- Give animals plenty of water to keep them hydrated - check their water is full all the time
- Consider buying booties to keep pets' paws and feet safe from getting burned on hot sand or hot pavements
- Let them have a swim if possible
- If travelling in a car with animals, stop regularly and give them frequent drinks of water
- Never leave pets in a car
This temperature comparison tool uses three hourly forecast figures. For more detailed hourly UK forecasts go to BBC Weather.
If you can't see the calculator, tap here.