Temperatures have been forecast to "feel like 25C" today, with Britain hotter than some parts of Spain, according to meteorologists.
The unexpected warm spell is set to offer warmer temperatures than select tourist destinations across Spain, including Oviedo and Santander, as well as areas surrounding Madrid and Malaga.
Britons have started to experience frostier temperatures, with many opting to switch on their central heating.
But this is set to change today, as areas across London and southern England will reach highs of 20 degrees.
NetWeather's Ian Simpson has attributed these hotter climates to the high winds forcing up air from the Mediterranean
WXCharts
NetWeather's Ian Simpson has attributed these hotter climates to the high winds forcing up air from the Mediterranean.
He said: "A marked change of weather pattern is forecast to set in next week, as temperatures are set to increase substantially, reaching well above average values for the time of year, due to a period of mainly southerly winds, pulling air masses all the way up from the Mediterranean.
"The warmth will peak on Wednesday and Thursday with many areas, especially in southern and eastern England, forecast to reach the low 20s Celsius on one or two of the days, which is not record-breaking for the time of year, but somewhat above the mid-October long-term average.
"One or two of the nights has potential to be more exceptionally warm.
"There is potential for parts of England and Wales to see overnight minima of 14 to 16C overnight Wednesday/Thursday, which is close to what these regions would normally expect to see as a daytime maximum around mid-October."
The weather agency's 10 day forecast says that the temperatures will have a "feel like" temperature of 25C.
Meanwhile, WXCharts has estimated that temperatures in the Spanish cities of Malaga and Salamanca, as well as Porto in Portugal will be lower than those across the UK.
Jim Dale, meteorologist for British Weather Services and social commentator, has forecast similar temperatures.
He added that he believes that air will be influenced by "the ashes" of Hurricane Leslie and even Milton.
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NetWeather has forecast London to feel like 25C on Wednesday
NetWeather
He said: “It is going to turn warmer this week as air arrives originating from Africa, and this could also contain the ashes of Hurricane Leslie and perhaps a trace of Hurricane Milton.
“Temperatures will peak around mid-week, and there will be a brief spell of T-shirt weather, particularly to the southeast and the east of the country."
Additionally, Simpson has said that he expects thunderstorms across the south, stating: "After a quiet day tomorrow, the weather will turn more unsettled again, and there is potential for the southerly winds to bring some thunderstorms, particularly through Tuesday and Wednesday, mainly for southern Britain, especially south-west England."
The end of October is expected to bring warmer temperatures than average, despite the brisk start to the month.