A “very limited” part of England’s south coast has seen a mid-September heatwave after three days of hot conditions, the Met Office has said.

According to forecasters, a heatwave can only be declared when an area sees three consecutive days of temperatures above a certain threshold.

In London this is 28C (82.4F), in counties near the capital such as Essex it is 27C (80.6C), while further away in areas such as Dorset and Somerset it is 26C (78.8F).

Temperatures soared across southern parts of the country earlier this week, including hitting 31.3C (88.3F) at Frittenden in Kent on Tuesday.

Met Office meteorologist Matthew Box said the mercury level reached 26.8C (80.2F) at Hurn in Dorset, near Bournemouth Airport, on Wednesday.

“At the moment it looks like pretty limited heatwave criteria has been met really, limited really almost just to the south coast, or parts of the south coast,” Mr Box said on Wednesday afternoon.

“Areas around Bournemouth have met that criteria.”

Commenting on heatwave threshold requirements, Mr Box said: “Most places have seen two days and haven’t met that third day criteria, so it hasn’t quite happened for a lot of places, really it’s been very limited to the south coast.”

He added: “However it’s been a pleasant warm spell… we’ve had temperatures exceed 30C (86F) of late, that doesn’t happen every September.”

According to the Met Office, the last time it recorded a September temperature of 30C (86F) or more was back in 2016 when 34.4C (93.9F) was logged in Gravesend in Kent.

Since digital records began in 1961, there had only been six previous years where temperatures of 30C (86F) or more were recorded in September: 1961, 1973, 1999, 2006, 2013 and 2016.

Mr Box explained that part of the reason the heatwave was not more widespread than expected on Wednesday was due to warm air being pushed by a cold front coming down across a central swathe of the UK.

There is also a cool breeze coming in from the North Sea, while some cloud covering parts of London and the South East helped “dampen” temperatures.

Mr Box said further data analysis due on Thursday would give a better indication of conditions on Wednesday, but said he expected areas meeting the threshold criteria to be limited to parts of Dorset and Hampshire.

Sunshine is forecast for much of the UK on Thursday, with temperatures dropping to a maximum of 23C (73.4F) or 24C (75.2F) in southern parts of the country.

Conditions will also be breezy in the south, while cloud will affect the far north of Scotland with some rain.

Settled conditions will continue through Friday and into the weekend, but by Saturday afternoon there could be some showers in southern counties of England.

Sunday will be cloudier with potentially heavy rain outbreaks for some southern counties, but elsewhere across the UK it will be mainly dry with sunny spells.

There is also a risk of some breezy and gusty conditions across England and Wales through the weekend.