A new record temperature for 2019 was set on Saturday, with the mercury reaching 34C at Heathrow in west London.
This was just short of the 35.6C June record set in 1976.
The forecast is expecting a “massive drop in temperature” to finish the weekend – although conditions will remain warm.
Then conditions will skyrocket again in time for next weekend.
“Temperatures pushing up into the upper 20Cs by next weekend”
“It will be nowhere near as hot as yesterday,” said Met Office meteorologist Alex Burkill.
“Today we’re looking at 26C to 28C in East Anglia, London and parts of Kent.”
While many places will see sunny conditions, isolated showers are predicted across southern England and Wales.
“Some places will see showers with bursts of 10 to 15mm in an hour, but it won’t be especially heavy,” said Mr Burkill.
Western Scotland and Northern Ireland are expected to start the day with showers, with stronger rain developing around lunchtime.
People flocked to the seaside to make the most of the hot weather on Saturday, while Tesco said sales of barbecue food had soared.
The supermarket predicted it would sell more than one million packs of sausages, 650,000 packs of burgers and 50,000 disposable barbecues over the weekend.
Several European countries have reported record temperatures this week, including France which hit an all-time heat record of 44.3C on Friday.
As a new working week approaches, rain is predicted through central parts of England on Monday.
Despite the threat of rain on Tuesday and Thursday, dry conditions are forecast for the rest of the week.
Then the weather will heat up again by the weekend.
Brian Gaze, of Weather Outlook, said: “Through the rest of the week it is expected to be dry with a good amount of sunshine in the south.
“There is also a growing signal for it to warm up again.
“Some model runs showing temperatures pushing up into the upper 20Cs by next weekend.
“The north it is likely to be more changeable early on but later on it could turn warmer there too.”