Temperatures in the capital are forecast to reach up to 22C on Wednesday in a throwback to summer.
The temperature rise gives Londoners a welcome respite from the chillier weather at the weekend where the mercury barely rose above double figures.
However, the summer-like blast is likely to prove short-lived, as “wet and windy” conditions are expected to return by the end of the week.
Met Office meteorologist Tom Morgan told The Times: “Temperatures are going to rise gradually, peaking probably on Wednesday, we might well see in some spots 20C, and 22C is not out of question, probably in eastern England - so East Anglia down towards the southeast.
“But it will be much milder compared to now for everyone.
“It’s possible we could exceed 20C in London.”
Sunshine is again expected on Thursday, with highs of 18C, before Friday brings with it “unsettled conditions with a mix of sunshine and showers”.
However, the Met Office said it expected Friday to “start fine” before showers begin.
Longer-term, the rest of the month is expected to see more unsettled weather, predicts the Met Office.
“All regions are likely to have some rain at times, which could be heavy. However, most of the rain, showers and strong winds are likely to be in the northwest with southeastern areas more often dry and bright,” said the forecaster.
“Temperatures will be above average and probably feeling warm in the brighter spells in southern areas.
“Later in October, there is a chance of more settled conditions developing, particularly in southern and eastern areas but with temperatures falling closer to average and some overnight frost and fog.
“Given the time of year, fog could be slow to clear.”
London’s October average is 16C.
The prediction of warmer weather comes after a chilly weekend, with temperatures barely escaping single figures.
Sunday morning saw the thermometer plummet to below 10C before warming up slightly into the double figures across the capital in the afternoon.
