Today has been the hottest September 30 for more than 100 years - with records being broken across the country.
In Cambridge, a temperature of 29.2C (84.6F) was recorded mid-afternoon, smashing the previous high of 27.8C (82F) recorded in Maidenhead, Berkshire, on the same day in 1908.
Aisling Creevey, a forecaster with MeteoGroup, the weather division of the Press Association, said: "Records have been broken for September 30 in a few places in the UK."
Those jetting off on holidays in search of sunshine may well find temperatures at home are just as good as those abroad.
Heathrow Airport can usually expect to see temperatures around 19C (66.2F)in September, and 15C (59F) in October.
Ms Creevey said: "We would expect the temperature for the last day of September to fall somewhere between these figures.
"But 28C (82.4F) has been recorded there today - 10C (50F) above average."
In Spain, temperatures of 29C (84.2F) have also been seen, while in Greece they ranged between 26C (78.8F) and 28C (82.4F).
There is now speculation that tomorrow could see the hottest October day ever recorded. The current record, set in March, Cambridgeshire, on October 1, 1985, is 29.4C (85F).
Ms Creevey said: "We're expecting another warm day tomorrow. It should be 29C (84.2F) in London."
Forecasters expect the weather to remain warm until the beginning of next week.
The warm weather could take travellers by surprise, with people hitting the roads in search of sunshine this weekend.
Travel information firm Trafficlink said: "The heat is likely to bring anything between 30% and 50% more traffic on to the 'usual summer routes' which would normally be OK at this time of year.
"Road authorities try and take out roadworks during the summer to ease the main routes, but this unexpected blast of heat means a lot of the repairs will remain in place which won't help."
Train companies are also expecting up to 25% more passengers as people rush to visit beaches and beauty spots.
Edward Welsh, from the Association of Train Operating Companies, said: "We're expecting thousands of families to pack their the buckets and spades, suncream and beach towels, and catch the train to seaside resorts and beauty spots."
Network Rail said today: "Just as yesterday, no rail passenger journeys are being significantly delayed by the hot weather.
"We fully expect no significant delays for the rest of the day. We continuously monitor the weather and act accordingly to make sure train services continue to run safely."
Hotels.com said it had experienced a 983% rise in searches to top British seaside destinations including Bournemouth and Weston-Super-Mare.
The most popular resort was Broadstairs in Kent, with a 275% increase in hotel searches compared with the same time last year.
The company said other popular spots included Salcombe in Devon, Skegness in Lincolnshire, Southend in Essex and Portsmouth.
The RSPCA has repeated its warning about the dangers of leaving animals in cars, conservatories or caravans during the hot weather after it received 170 reports from people worried about pets in the last week.
The charity said this is three times as many calls as during the same week last year.