UK Weather Flips: 26°C Warmth Gives Way to Rain and 6°C Nights

The new week will bring a clear change in the weather across the United Kingdom. Monday and Tuesday will still feel pleasantly warm in many central and southern areas, but an Atlantic-driven change will gradually introduce rain, lower daytime temperatures and much fresher nights as the week progresses.

UK weather 17–23 August: the week at a glance

Warmest start: London, Oxford, Birmingham and Southampton reach around 25–26°C on Monday.
Atlantic change: rain spreads from Scotland and the northwest toward Wales, central and southern England from Tuesday into Thursday.
Cooler second half: many northern areas fall back to around 15–18°C by Friday and the weekend.
Fresh nights: inland and northern locations drop below 10°C; Glasgow may fall to around 6°C by Sunday morning.
Wettest signals: Aberdeen around 15 mm Tuesday, Cardiff around 13 mm Thursday, Southampton and Norwich around 10 mm Thursday.

The warmest weather will be concentrated across southern and central England at the beginning of the period. London, Oxford, Birmingham and Southampton will all reach around 25–26°C on Monday, while eastern England may remain above 20°C into Tuesday. Farther north, Scotland will be substantially cooler, mostly between 16 and 19°C.

But the warm start will not last.

From Tuesday into Thursday, bands of rain will increasingly affect Scotland, northwest England, Wales and eventually parts of southern and eastern England. Behind them, temperatures will fall. By Friday and the weekend, many northern areas will struggle to reach 15–18°C, while even southern England will generally stay close to 19–22°C.

The nighttime change will be equally noticeable. Early in the week, London may remain near 20°C overnight, but by the weekend some inland and northern locations will fall below 10°C. Glasgow could drop to around 6°C by Sunday morning, with Belfast, Edinburgh, Newcastle and Birmingham also seeing distinctly chilly late-August nights.

So let’s compare the seven-day weather trend across the same locations around the United Kingdom, from Monday, 17 August, through Sunday, 23 August.

Scotland Weather: Rain First, Then a Cooler Late-August Feel

Scotland stays cooler than southern England throughout the week, with the strongest early-week rain signals and notably chilly nights by the weekend.

As always, we begin with Scotland, where the week will be cooler and considerably wetter than farther south.

Aberdeen

faces one of the wettest spells early in the forecast. Monday reaches only around 16°C, before a slightly warmer 19°C on Tuesday. However, Tuesday may produce close to 15 mm of rain, making it one of the more significant rainfall days in this UK forecast. From Wednesday onward temperatures fall again, eventually dropping to only around 13–16°C during the second half of the week. Nights become increasingly cool, reaching about 9°C by the weekend.

Edinburgh

starts the week around 17°C on Monday and 19°C on Tuesday. Monday itself may bring around 7 mm of rain, followed by lighter showers during the middle of the week. There should be a drier window during the weekend, but temperatures remain subdued. Daytime highs generally settle near 16–18°C, while Sunday morning could fall to around 9°C.

Nearby Glasgow also begins on a wet note. Around 5 mm of rain is forecast for Monday, with additional lighter precipitation on Tuesday and Wednesday. Temperatures remain unusually steady, mostly between 16 and 18°C, but the real change comes at night. Minimum temperatures fall from around 15°C on Monday to only 6°C by Sunday morning. That will give the final weekend a distinctly autumn-like start despite it still being August.

Newcastle: A Gradual Slide Into Cooler Weather

Changeable weather is expected in Newcastle, but the most striking feature will be the temperature trend.

Monday and Tuesday reach about 19°C, with rain most likely on Monday. After that, temperatures step downward almost every day: around 18°C Wednesday, 16°C Thursday, 15°C Friday and only 14–15°C during the weekend.

By Sunday morning, the temperature may fall to around 9°C.

So while southern England begins the week in summer mode, northeast England will be experiencing something much closer to early autumn by the end of it.

Belfast: Wet Start, Chilly Finish

Belfast

gets close to 20°C on Monday, but that warmth comes with rain. Open-Meteo indicates around 7 mm of precipitation on the first day of the week.

Wednesday brings another wetter spell of roughly 5 mm, while temperatures fall into the 15–17°C range for most of the second half.

The weekend looks considerably drier, but there is a trade-off: Saturday and Sunday mornings could drop to only 7–8°C.

An umbrella will be useful at the start of the week; a warmer layer may be more valuable by the weekend.

Hull: Warmest on Tuesday, Then a Sharp Cooldown

The trend in Hull shows the transition particularly well.

Monday reaches around 22°C, and Tuesday could climb to 23°C, making it one of the milder northern and eastern locations.

Then the Atlantic change arrives.

Wednesday falls to around 20°C, Thursday to about 18°C, and the weekend struggles at only 16–17°C. Rain is not constant, although Thursday and Friday bring an increased shower risk.

Nighttime temperatures also fall toward 9–10°C by the weekend.

Liverpool: Several Wet Days Before a Drier Weekend

Liverpool

will see a less dramatic temperature range but a much wetter middle of the week.

Monday starts near 20°C, followed by around 18°C on Tuesday. Rain increases from Tuesday into Thursday, with roughly 4–6 mm possible on each of these days.

Friday and the weekend become much drier, but temperatures remain modest at around 17–19°C.

The warmest nights occur at the start of the week, near 16°C. By Sunday morning, minimum temperatures fall to approximately 10°C.

Manchester: Warm Monday, Then Repeated Rain

Manchester

begins the week fairly warm, reaching about 22–23°C on Monday.

That warmth disappears quickly.

Tuesday falls to around 19°C and Wednesday to about 18°C. Rain becomes increasingly important, with around 5 mm on Tuesday and more than 7 mm possible on Wednesday.

Conditions become drier from Friday onward, and Saturday may briefly recover to almost 20°C, but Sunday cools again to around 18°C.

This will therefore be a week of two halves: warm and unsettled first, cooler and drier later.

Norwich: Warm East, Then a Wetter Thursday

Eastern England holds onto summer warmth a little longer.

Norwich

reaches around 22°C on Monday and 23–24°C on Tuesday. Rain is possible Tuesday, but Wednesday may be largely drier.

The more significant change arrives Thursday. Temperatures fall to around 18°C, while Open-Meteo currently indicates close to 10 mm of precipitation.

Friday through Sunday stays cool, generally around 18°C, with only limited rainfall.

Birmingham: From 26°C to the High Teens

One of the strongest temperature contrasts of the week occurs in Birmingham.

Monday may reach approximately 26°C, making it one of the warmest cities in the UK at the start of the forecast.

Tuesday drops to around 23°C.

Then the cooler air arrives decisively: 19°C Wednesday, 17°C Thursday and Friday.

Thursday is also the wettest day, with around 5 mm of rain currently forecast.

Saturday may briefly recover to around 20°C before another cooler day on Sunday. Nights become surprisingly fresh, falling to about 9°C by the end of the week.

Oxford: Summer at First, Cooler and Wetter by Thursday

Oxford

follows a similar pattern.

Monday is warm at around 26°C, followed by approximately 24°C Tuesday.

Wednesday falls to around 21°C, while Thursday brings the main weather change: temperatures near 19°C and around 6 mm of rain.

Friday and the weekend stay near 19–21°C.

Perhaps the biggest surprise comes at night. After a very mild 18°C Monday night, temperatures could fall to only 9°C by Saturday morning.

London: A Warm Monday, but No Return of Extreme Heat

The new week starts warm in London, but there is currently no signal for another major heatwave during this forecast period.

Monday reaches approximately 26°C, with a remarkably warm nighttime minimum close to 20°C.

Tuesday remains pleasant at around 24°C.

After that, temperatures gradually decrease: around 22°C Wednesday and Thursday, close to 20°C Friday, and generally 20–22°C over the weekend.

Rainfall is mostly limited. Thursday currently has the largest total, at only around 2–3 mm.

The more noticeable change is at night, with minima dropping toward 11–14°C by the weekend.

So London begins the week in summer, but ends it with much fresher late-August conditions.

Wales Weather: Cardiff Turns Wet Around Midweek

Wales follows the Atlantic transition clearly: a relatively mild start gives way to a wetter and cooler midweek period.

Moving west into Wales, Cardiff begins fairly warm at approximately 23°C Monday and 22–23°C Tuesday.

Wednesday marks the first substantial change, with temperatures dropping below 19°C and around 6 mm of rain.

But Thursday currently looks much wetter.

Open-Meteo indicates around 13 mm of precipitation, one of the highest daily totals among the locations in this forecast.

Temperatures remain only around 18–19°C through Friday.

Saturday could briefly improve to around 22°C and mostly dry conditions, before another cooler and potentially showery Sunday.

Southampton: Warm Start, Wet Thursday

Southampton

is another location where the week begins very differently from how it ends.

Monday reaches about 26°C, Tuesday around 25°C.

By Wednesday the temperature is down to approximately 21°C.

Thursday becomes the main wet day, with around 10 mm of rain possible and a maximum temperature of only 19°C.

The weekend becomes mostly dry again, but daytime highs stay close to 19–20°C.

Nighttime temperatures eventually fall toward 11°C.

Plymouth: Mild Start, Cooler Air and a Late Sunday Rain Risk

Finally, Plymouth starts the week mild and relatively pleasant.

Monday reaches around 23°C, while Tuesday may be slightly warmer at 24°C.

Wednesday and Thursday fall to around 19–20°C, with some rain but currently nothing particularly extreme.

Friday and Saturday remain near 20°C and look mostly dry.

There is, however, a new rainfall signal for Sunday, when around 5 mm may return while temperatures fall back to approximately 19°C.

Saturday morning could also be surprisingly chilly for southwest England, near 8–9°C in the current model run.

UK city comparison: warmest start, wettest days and coolest nights

Location	Warmest daytime signal	Main rain signal	Coolest night signal
Aberdeen	~19°C Tuesday	~15 mm Tuesday	~9°C weekend
Edinburgh	~19°C Tuesday	~7 mm Monday	~9°C Sunday
Glasgow	~18°C	~5 mm Monday	~6°C Sunday
Belfast	~20°C Monday	~7 mm Monday	~7–8°C weekend
Manchester	~22–23°C Monday	>7 mm Wednesday	Cooler late week
Norwich	~23–24°C Tuesday	~10 mm Thursday	Cooler late week
Birmingham	~26°C Monday	~5 mm Thursday	~9°C late week
Oxford	~26°C Monday	~6 mm Thursday	~9°C Saturday
London	~26°C Monday	~2–3 mm Thursday	~11–14°C weekend
Cardiff	~23°C Monday/Tuesday	~13 mm Thursday	Cooler late week
Southampton	~26°C Monday	~10 mm Thursday	~11°C late week
Plymouth	~24°C Tuesday	~5 mm Sunday	~8–9°C Saturday

UK Weather Trend: What Matters Most This Week?

The main story from 17 to 23 August 2026 is not extreme heat or a major storm. It is the transition from a warm late-summer start to a cooler Atlantic pattern.

The highest temperatures are concentrated on Monday and Tuesday:

London around 26°C
Southampton around 26°C
Oxford around 26°C
Birmingham around 26°C
Norwich and Hull around 23°C

Scotland remains much cooler throughout.

The wettest individual signals currently include:

Aberdeen — around 15 mm on Tuesday
Cardiff — around 13 mm on Thursday
Southampton — around 10 mm on Thursday
Norwich — around 10 mm on Thursday
Manchester — around 7 mm on Wednesday
Belfast — around 7 mm on Monday

The most important temperature change comes after Tuesday.

By the end of the week, many places that begin in the low or mid-20s will be sitting in the high teens, while parts of Scotland and northeast England may struggle to reach even 15–16°C.

And perhaps the clearest sign that late summer is beginning to change: overnight lows by the weekend may drop below 10°C across several northern and inland locations.

So the UK gets a little taste of summer at the beginning of the week — but by Friday and the weekend, the Atlantic will be firmly back in charge.

Forecast period: 17–23 August 2026
Weather data source: Open-Meteo Forecast API
Locations and editorial structure: aligned with the Pogodnik UK forecast format.

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UK weather FAQ: 17–23 August 2026

When will the warmest weather occur?

The warmest conditions are concentrated on Monday and Tuesday, with London, Southampton, Oxford and Birmingham reaching around 25–26°C.

When does the cooler Atlantic air arrive?

The main transition develops from Tuesday into Thursday, first affecting Scotland and the northwest before spreading farther south and east.

Where is the heaviest rain expected?

Among the supplied locations, Aberdeen has around 15 mm on Tuesday, Cardiff around 13 mm on Thursday, and Southampton and Norwich around 10 mm on Thursday.

How cold could the nights become?

Several inland and northern locations may fall below 10°C by the weekend. Glasgow could drop to around 6°C by Sunday morning, with Belfast, Edinburgh, Newcastle and Birmingham also turning notably chilly at night.

Will London see another heatwave?

No major heatwave signal is present in the supplied forecast. London peaks around 26°C on Monday, then cools gradually toward 20–22°C by the weekend.

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