Exact date 'mini-heatwave' will hit UK with temperatures as high as 27°C (2025)

It’s not just London Marathon runners who need to stay hydrated this weekend.

As much as it might still feel chilly today, the UK weather will see temperatures climb over the coming days as northwesterly warm air flows from Europe.

This change in wind direction will bring some of the warmest weather of the year so far, including a mini-heatwave next week.

‘It’s warming up over the weekend,’ the Met Office said on X, sharing a video of a heat map showing the UK getting more orange by the second.

‘By early next week, maximum temperatures in the high teens or low 20s Celsius will be widespread,’ the UK weather service said.

‘If you like cooler conditions, head to coastal areas where it won’t be quite as warm.’

But where will it be warm over the coming days? And when will it be hottest?

Saturday

The UK’s thermostat is being slightly cranked up tomorrow. Saturday’s temperatures will be between 13°C and 18°C.

Cloud will smear the skies grey in the west, with patchy rain and drizzle helping to keep the weather more stereotypically British.

According to the Met Office, the rain will creep in overnight, with the heaviest spells in western Scotland, Wales, and south-west England.

The stubborn rain will only begin to clear around midday, helping give the temperature a slight boost to the mid-10s. The east and Northern Ireland will be on the sunnier side, forecasters said, with cloudy starts in the morning clearing a path for dry, sunny spells.

London will be the warmest part of the UK tomorrow at 18°C, only starting to cool off from 7pm.

Sunday

Two major marathons take place on Sunday, in London and Manchester.

But runners won’t need to pack their raincoats. After a cloudy start, both cities will see hours-long sunny spells and warm weather to match.

By 10am, London and Manchester will be 15°C and 14°C respectively, the two hottest places in the UK.

And it’ll only get hotter from there. At 4pm as the races come to an end, the Met Office expects the mercury in Manchester to have risen to 19°C as a gentle south-westerly breezeblows.

In the capital, it will have tipped over to 21°C.

Elsewhere in the country, a band of rain will slowly creep over from the west in the early hours.

Northern Ireland will avoid the worst of the downpours, but from 7am or so, the majority of western and central Scotland will be soaked. Some parts will see as much as 8mm of rain per hour.

Scots probably won’t need to pack and sunscreen alongside their umbrellas, unfortunately, though some cities such as Edinburgh and Glasgow will experience temperatures in the mid-10s.

When will the mini-heatwave start?

From Monday onwards, Britain will bask in a mini-heatwave.

The BBC weather forecast says temperatures will climb to 23°C – being overall ‘very pleasant in the sunshine’ – before peaking at 27°C in the Midlands and south-east England on Wednesday (May 1).

This will be the warmest the UK has been since September, when it was briefly even warmer than Barcelona.

The Met Office’s forecast is slightly lower than the BBC’s, however. The agency doesn’t expect it to get warmer than 25°C in London at about 4pm – freezing, in other words.

Elsewhere, the temperatures will be in the low 20s and the high-10s across the Scottish coast and Northern Ireland.

Next week’s temperatures, while sweltering, are typically what a warm spell in April will reach, the Met Office says.

A heatwave – a regular-sized one, not a mini – would need to see the temperature be above 25°C for three days or longer.

Get in touch with our news team by emailing us at webnews@metro.co.uk.

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