The all-time high temperature recorded in Britain, set on July 25, 2019, in Cambridge, is 38.7 degrees Celsius, or about 102 degrees Fahrenheit.
Several forecasters said that record could fall on Tuesday.
Paul Davies, the chief meteorologist at the Met Office, Britain’s national weather service, told Sky News on Monday that “there’s a good chance now of hitting 40 or 41 degrees Celsius” on Tuesday.
Jonathan Porter, the chief meteorologist at AccuWeather, said that with a forecast high of 39 degrees Celsius, “there will be numerous records broken across the area.”
And the chief executive of Britain’s Royal Meteorological Society, Professor Liz Bentley, said that the temperature could climb as high as 42 degrees Celsius, or about 108 degrees Fahrenheit.
“This is an extreme scenario,” said Professor Bentley. “It really is a consequence of climate change. I think it’s important we get that message across. We’re likely to see more of this going forward.”
Professor Bentley warned on Monday of potential infrastructure problems across the nation in the coming days, including melted roads, power outages, bent railway tracks and wildfires.
Wildfires are not uncommon in Britain, although they are rarely severe. A spokesman for the London Fire Brigade said on Monday that there was a high possibility of exceptionally large grass fires because of the hot weather.
Pat Goulbourne, assistant commissioner for the London Fire Brigade, said that the Met Office was “urging people to continue to take extra care and help us prevent fires on open land.”
Mr. Porter, from AccuWeather, emphasized that nighttime won’t bring much relief. In London, the low temperature was expected to fall to just 76 degrees Fahrenheit, a typical high temperature for this time of year, he said.
“The temperatures don’t fall much during overnight hours,” he said. “It just prolongs it and puts more and more stress on people’s bodies.”