UK Weather Forecast: 27C Peak, Then Rain and Thunderstorms From Tuesday

The Met Office’s national forecast for the coming week does not contain a single temperature figure. It says Sunday will be “a little higher than Saturday”, and that through midweek temperatures will be “continuing to rise slightly”. That is the whole of what the official text commits to.

For an actual number you have to go to a location forecast, and the one that matters most for a heat story is London. It peaks at 27C on Wednesday.

The more useful part of the forecast is not the heat at all. It is that the settled spell ends on Tuesday.

What is the UK weather forecast this week?

Fine and dry until Monday, then unsettled from Tuesday with showers, thunderstorms and longer spells of rain moving northwards.

That last clause is the Met Office’s own wording, and the direction matters: the wet weather moves north, so southern England gets it first and Scotland later.

Tonight is cloudier over northern Scotland with a few light showers. Elsewhere it is a chilly night with long clear spells and mist or fog forming in rural areas. Sunday is high pressure again — settled, largely dry, sunny spells, light winds, with an isolated shower possible near northern coasts. Monday holds.

London day by day

Two things worth reading off that table. The overnight minimum climbs all week, from 13C on Saturday night to 18C by Wednesday — that is what makes a warm spell feel like one, more than the daytime figure. And the rain probability steps up rather than ramping: under 5%, under 5%, 10%, then 30%, 30%, 50%, 50%.

These are Greater London figures. Nothing in this table is a national number.

When do the thunderstorms arrive?

From Tuesday, on the Met Office’s wording, and they are part of a broader breakdown rather than an isolated event.

The extended outlook is blunter: “showers or longer spells of rain are possible across many parts of the UK. Some heavy bursts and thunderstorms are likely at times.” That runs into early September, with rainfall “probably above average for the time of year” and “the potential for some stronger winds at times”.

If you want a single sentence for the fortnight: warm and dry through Monday, then changeable, wetter than usual for late August, with thunder in the mix.

Are there any Met Office weather warnings?

No. Not one, for any day from Saturday 22 August to Friday 28 August.

This is worth stating plainly because a forecast mentioning thunderstorms and a warning about thunderstorms are different things, and headlines tend to blur them. The Met Office’s warnings page has a tab for each of the next seven days and all seven currently read “No warnings”.

That can change quickly. Thunderstorm warnings are usually issued a day or two ahead, not a week, precisely because the storms are hard to place until they are close. If one is issued for midweek it will not contradict anything here — it will be the system doing what it does.

Is the UK really getting 29C this week?

Not according to any Met Office forecast read for this page.

The national text gives no figures. London, which is normally the warmest part of the country, tops out at 27C on Wednesday. Nothing in the seven-day London forecast reaches 29C at all.

That is a check of one location and the national text, not a survey of every station in Britain, so this is not a claim that nowhere will see 29C. But if a 29C figure is circulating for this week, it is not coming from the Met Office’s published forecast, and the gap between “a model run suggested it” and “the Met Office forecasts it” is where most overheated weather coverage lives.

For context on what this summer actually delivered: the heat that peaked on 13 August reached 38.1C at Kew Gardens, the fifth-highest temperature ever recorded in the UK. Twenty-seven is a pleasant late-August Wednesday. It is not a heatwave, and the Met Office is not calling it one.

Why has the rain kept not arriving?

Because it is the hardest part of the forecast, and the Met Office has said so itself.

In its 13 August assessment the agency noted that “several forecast systems have previously suggested wetter weather only for the rain to weaken or fail to materialise as expected”, and that confidence in rainfall remains lower than in temperature. That was written about a different week, but the caveat is structural rather than about that particular system.

There is a second problem even when the rain does show up. Much of it moves through quickly, and on ground this dry a lot of it runs off rather than soaking in. What the drought areas need is prolonged, steady rain, which is not what a line of thundery showers delivers.

What about the rest of the summer and into September?

Changeable. The Met Office expects the unsettled theme to continue at first, with showers or longer spells of rain across many areas, “perhaps heavy and thundery in places”, before drier weather possibly becomes more prevalent later in September, especially in the south and southeast.

Temperatures are expected to be near normal at first and possibly warmer later, with the chance of some hot spells in the south. Our September forecast page goes through that outlook in more detail, including why the Met Office’s own monthly forecast stops partway through the month.

Will it be hot this weekend?

Warm rather than hot. Sunday is the better of the two days — settled, largely dry, sunny spells — and in London it reaches 24C against Saturday’s 22C. The Met Office describes Sunday nationally as “largely fine and dry with sunny spells”.

When does the weather change?

Tuesday 25 August. Monday is the last of the fine, dry days in the current run; from Tuesday the Met Office has showers, thunderstorms and longer spells of rain pushing northwards across the country.

Is this a heatwave?

No. A UK heatwave has a formal definition based on three consecutive days at or above a county-specific threshold, and a 27C Wednesday between cooler days does not meet it anywhere. The Met Office is not using the word for this week, and neither is this page.

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