by A heat-health alert has been issued for most parts of England as temperatures could reach 32C (89.6F) midweek.
The UK Health Security Agency’s yellow warning is in place across seven regions until 21:00 BST on Sunday.
It means that the elderly and those with pre-existing health conditions should take extra care.
The hot conditions will be also be felt in Wales, while parts of Scotland and Northern Ireland could see “unseasonably high temperatures”.
Regions included in the warning are: London, the South East, the South West, the East and West Midlands, the East, North West and Yorkshire and Humber.
Temperatures reached 30C on Monday in southern England and south-east Wales, according to the Met Office.
The hot weather comes after what has generally been regarded as a summer of poor weather for much of the UK.
While July in particular was wetter and cooler than average with the maximum temperature failing to regularly reach 20C, the previous month was the UK’s hottest June on record.
The warm conditions will continue through Tuesday with highs of 31C expected.
“We will see good sunny conditions through the week with cloudless skies, and some high temperatures by the time we get to Wednesday and Thursday, where we could see 31, maybe 32C,” Met Office spokesman Oli Claydon told the PA news agency.
He said the high temperatures would be “quite widely spread” across the UK, with the hottest conditions mainly being felt in south-east and central England.
Mr Claydon warned that Wednesday night could be a particularly warm with temperatures potentially not dropping below 20C, which is what is termed a “tropical night”.
There could also be a tropical night on Thursday, he said.
The Met Office said that tropical storms in the far western Atlantic, as well as deep areas of low pressure, have helped to amplify the jet stream – a fast wind high in the atmosphere – over the Atlantic Ocean. This has led to high pressure “dominating over the UK”, it said.
The forecaster added that temperatures could also hit 31C on Friday, although there could be more cloudy weather and chances of rain in the far north-west of Scotland.
Conditions could change over the weekend, and Mr Claydon said there was “no indication at the moment of another strong heatwave after this”.
Average temperatures are expected to return by the middle of next week.
Heatwaves are becoming more likely and more extreme because of climate change.
Last year the UK recorded temperatures above 40C for the first time. Scientists said that would have been “virtually impossible without climate change”.
The Met Office has also explained the reason for some “picturesque” sunsets across the UK in recent days.
Forecasters say it is due to “Saharan dust” and it is due to cover parts of the country later this week.
