"Unseasonably cool" temperatures are announcing the arrival of autumn in the UK as the summer starts to come to a close.
With the change in season drawing closer, a Met Office spokesman said temperatures are unlikely to hit 20C over the next few days - three degrees lower than the average for August.
While it is not uncommon for August to be marred by unsettled weather, the chill in the air is "unusual".
He said: "The last week has been unseasonable cool for August. The rain and wind isn't that unusual but it certainly has been cool for this time of year.
"The first two weeks of the month were actually slightly above average so overall August has been quite normal.
"We are coming towards the end of summer though, so we can't expect the high temperatures to last much longer."
Meanwhile, a weather expert at MeteoGroup said the unsettled weather this week is more what we would expect to see in September.
Some sunshine is expected to break through over the long weekend, with Saturday and Sunday remaining cool but largely dry, with a few scattered showers particularly in the North.
Monday, which is a Bank Holiday for England, Wales and Northern Ireland, will see heavier rain and brisk winds.
The unsettled weather will linger for a further few days before hopefully settling down to steady temperatures of around 20C, the Met Office spokesman added.
It is in strong contrast to the blistering hot August Britain enjoyed last summer, when temperatures reached 34.1C.
The disappointing temperatures has prompted a last-minute rush for overseas holidays, the director of First Choice and Thompson reported, as Brits hope to catch more sunshine.
Andrew Flintham said: "This time of year is always popular for holidays, however with the predicted bad weather and the end of the summer of sport we're seeing more customers rush to squeeze in a last-minute break before the start of the new school year."
More than two million British holidaymakers are already booked to head overseas during the August Bank Holiday, Abta said.
A spokesman for Abta said:"Typically, bad summer weather in the UK makes many people long for the sun and head off overseas.
"Next week temperatures in the UK are predicted to struggle to hit the high teens and the country will be covered by a bank of clouds, so many may be tempted to book a late break to the Mediterranean where temperatures will be in the 30s and hours of sunshine are guaranteed."
Back in Britain, 5.1 million people are planning an overnight holiday trip this weekend, VisitEngland said.
Meanwhile, around one million people are expected to be drawn to Notting Hill Carnival, Europe's biggest street carnival event, which will see hundreds of musicians and dancers join floats for a procession through west London on Sunday and Monday.