A plume of warm air from the Canary Islands pushing temperatures to record levels shows no sign of retreating until after the first week of November.
The next few days, while not as hot as the weekend, will be unusually mild as Halloween trick or treaters head out in T-shirts this year.
The warm weather is in part being driven by energy left in the atmosphere from the historic summer heatwave.
Sea and ground temperatures still warm from the past few months will help to push temperatures higher in the Continental plume.
Jim Dale, meteorologist for British Weather Services, said: “The sea and land temperatures are still warm after the summer, and this is because apart from the brief cold spell at the start of the month, it has been unusually mild through autumn.
“Temperatures are likely to stay above average for the time of year through next week and into the second week of November, although they will gradually come down from the highly unusual levels of this weekend.
“It is still going to be relatively mild on Halloween, with highs of 17C possible in the south and between 10C and 12C in the north, and it will be mostly settled, so not scary weather at all.”
Stubborn high pressure helping to steer warm air in from the south is more typical for summer than the run up to winter.
It has joined forces with low pressure to the west of the UK to form a channel of air from France, Spain and the Canary Islands.
The so-called “blocking high” over Europe is keeping low pressure from moving into Britain and shaking up the weather.
Mr Dale, author of Weather Or Not? said: “This is a very unusual weather pattern in that what we are seeing is a summer set up rather than an autumn set up.
“A blocking high over Europe is helping to bring in this warm air, while keeping low pressure to the west and any cold air over Scandinavia.
“This is not the sort of weather that we expect to see at this time of year, but it is a sign that the weather is changing and helping to drive this spell of warm weather will undoubtedly be the effects of climate change.”
Weather models reveal warm air swamping the UK through next week with temperatures hitting the mid- to high-teens across southern and eastern Britain.
Scotland and the north will be cooler although here temperatures will still lift into the low- to mid-teens–much higher than average for the start of November.
But with low pressure nearby, swathes of Britain will be in the firing line for outbreaks of heavy rain.
Bookmaker Coral has cut the odds to 6-4 on the wettest November on record amid forecasts for above-average rainfall in parts.
Spokesman John Hill said: “It is going to be a very damp start to the new month, and with heavy downpours predicted to fall over the next seven days, we have slashed the odds in half on a record-wet November.”