A heat alert has been issued for some parts of the UK this week as temperatures are predicted to reach 33C on Monday.
The mercury will soar in central, southern and eastern England, the Met Office said, amid a heatwave that will leave some parts of the country hotter than Jamaica, the Maldives and the Bahamas.
Highs of 29.5C were seen in London and the South East on Sunday while Scotland recorded its hottest day of the year so far, with the mercury hitting just below 29C.
The hot weather looks set to last into next weekend, with temperatures forecast to reach 35C on Sunday.
Those in affected areas advised to shade or cover windows and check on the vulnerable and the elderly.
What is a Level 3 Heat Alert?
A Level 3 Heat Alert is triggered when the Met Office confirms threshold temperatures for one of more regions have been reached for one day and the following night, and the forecast for the next day has a greater than 90% confidence level that the day threshold temperature will be met.
This stage requires social and healthcare services to target specific actions at high-risk groups.
NHS England and NHS Improvement groups will assemble mutual aid when requested by local services.
Will we have another heatwave?
The Met Office’s definition of a heatwave is when a location records a period of at least three consecutive days with daily maximum temperatures reaching or exceeding the heatwave temperature threshold, which varies by county.
In such conditions, the Met Office issues a heat-health warning which gets sent on to health and social care professionals, so they can work to minimise the impact of the high temperatures on people’s health.
Meteorologist Annie Shuttleworth said: “We’re at the start of a potentially relatively long spell of warm weather for much of the UK away from the far North West where it’s likely to be a bit cooler and cloudier.”
She added: “For some areas, namely parts of the South West, this is probably the start of their heatwave, but for the more widespread heatwave threshold temperatures to be met it’s likely to be from Sunday, so Sunday, Monday, Tuesday.”
Dr Agostinho Sousa, head of extreme events and health protection at the UK Health Security Agency, said: “Heat-health alerts have now been issued to the majority of the country, with temperatures set to remain consistently high throughout the duration of next week.
“Most of us can enjoy the hot weather when it arrives, but it is important to keep yourself hydrated and to find shade where possible when UV rays are strongest, between 11am and 3pm.
“If you have vulnerable family, friends and neighbours, make sure they are aware of how they can keep themselves protected from the warm weather.”
The UK’s record high for 2022 currently stands at 32.7C, recorded at Heathrow on June 17.
The UK Health Security Agency (UKHSA) heat-health warning will be in force from July 11 until July 15, including regions in the South East of England.
Met Office forecaster Greg Dewhurst said: “High pressure is going to dominate tomorrow, with lots of sunshine, particularly in England and Wales.
“In Scotland and Northern Ireland it will be somewhat hazy at times with thick cloud moving in from the north-west, possibly bringing some rain at times.
“But for most of us it will be a dry and sunny day, well into the high 20s from the morning, with central, southern and eastern parts of England to possibly see maximum highs of 33C.
“So it’s very possible tomorrow will be the hottest day of the year so far, it will certainly be on par with the existing record, maybe more.
“It will also be very warm overnight going into Tuesday, remaining in the low 20s in cities, so many may experience an uncomfortable night.”
The hot spell looks set to subside later in the week, when a cold front is expected to start pushing in.
However, Mr Dewhurst said temperatures will remain in the mid-to-high 20s until the end of the week.