Britain is set to experience “freakishly-hot” temperatures ahead of Halloween as an “African plume” will push the mercury up to 23C (73F), forecasters say.
The Autumnal Indian Summer is set to end the hottest year the UK has ever experienced.
Monday is forecasted to be the beginning of the warm run, which will last for up to six days.
Wednesday is predicted to be the hottest day at around 22C.
The South is expected to be warmer than the North.
The UK should expect sunny spells alongside the hot temperatures, with some showers.
Meteorologists have predicted that the mild conditions will last up to Halloween on October 31.
Netweather forecaster Nick Finnis said: “Some computer models show 22C or 23C by midweek, bringing an Indian Summer.
“An exceptionally-warm plume of air from northwest Africa looks like being pumped across Europe and to Britain, with up to the low 30s in France, and over 20C in southern Britain.”
Met Office forecaster Marco Petagna said: “There’s a good signal for higher temperatures thanks to a southerly airstream with very mild or warm air.”
A Met Office forecaster said: “Sunday has sunny spells for many, with Monday dry with sunny spells in the South as rain clears the North.