Forecasters say that highs of 34C could be recorded in England this week as the weather heats up going into the summer months.
The blistering temperature affecting Spain will sweep in towards the end of the week, bringing with it temperatures that could exceed Jamaica and Miami.
The Met Office said a high-pressure system around the south of the country is bringing the warm weather and then as it moves east on Thursday it allows even hotter air from the south to come in.
With hotter conditions forecast, the Met Office and the UK health security agency have issued a three-day heat alert.
But is the UK about to experience a heatwave?
A heatwave is an extended period of hot weather relative to the expected conditions of the area at that time of year, which may be accompanied by high humidity, the Met says.
Will Friday's hot weather last into the weekend❓
A cold front could change things for some but not for others 🌡️
Though there's still some uncertainty over its timing and how much of the UK will retain the heat 🤔 pic.twitter.com/yEsbBz2asc
— Met Office (@metoffice) June 14, 2022
A UK heatwave threshold is met when a location records a period of at least three consecutive days with daily maximum temperatures meeting or exceeding the heatwave temperature threshold.
The threshold varies by UK county. For Surrey, Berkshire, Buckinghamshire, Bedfordshire, Hertfordshire and Cambridgeshire it is 28C. In Lincolnshire it is 27C and in Yorkshire it is 26C.
Forecasters have said some parts of England may experience temperatures of 28C (82F) in the North East and North West and 30C (86F) in the southeast on Friday.
Agostinho Sousa, head of extreme events and health protection at the UKHSA, said: "Temperatures are forecast to reach 30C in some parts of the south on Friday and we want everyone to enjoy the hot weather safely when it arrives and be aware of good health advice for coping with warmer conditions.
"During periods of hot weather it is especially important to keep checking on those who are most vulnerable, such as older people and those with heart or lung conditions.
"Make sure to look out for signs of heat exhaustion and follow our simple health advice to beat the heat."
Met Office deputy chief meteorologist Dan Rudman said the temperature predictions are unusual for this time of year.
"Many areas will also see some warm nights with minimum temperatures expected to be in the high teens or even low 20Cs for some overnight," he said.
"The heat is a result of a mix of home-grown warming in the day due to high pressure, as well as a southerly airflow introducing some of the warm air from the continent to UK shores."
The highest temperature reached in the UK so far this year was 27.5C at Heathrow on May 17.
An Environment Agency spokesperson said there is a low-risk of drought but warned further hot, dry weather could put pressure on some areas.