Quick answer: No fourth heatwave is confirmed for London right now. The Met Office says the next few days (20-24 July) will be dry and warm but not extreme. Its long range outlook for 25 July to 18 August points to a changeable spell with rain and sunny spells mixed in, though there are early hints that hot, dry conditions could build again as August begins.

Londoners have had a summer to remember in 2026. There have already been three heatwaves, a rare red extreme heat warning, and more days above 30C than the whole of 1976. So it is no surprise people are asking whether another one is on the way. Here is what the Met Office and other forecasters are actually saying right now, and what to watch for over the coming weeks.

This article pulls together the latest official Met Office updates, the UK Health Security Agency’s alert history, and a look back at exactly how hot each of London’s three heatwaves this year has been. Whether you are planning a weekend out, packing for a trip, or just wondering if you need a fan on standby, you will find a clear, up to date answer below along with practical tips for staying safe if the heat does return.

Question	Current Status
Is a heatwave happening in London today?	No
Is a heatwave forecast for this week (20-24 July)?	No
Is a heatwave forecast for late July / early August?	Uncertain
Are there any heat health alerts active for London?	None currently
Has London had heatwaves already this year?	Yes, three

2026 Heatwave	Dates	Peak Temperature	Notes
First heatwave	Started 22 May	35.1C at Kew Gardens, London (26 May)	Broke the UK’s previous May record of 32.8C, set in 1922
Second heatwave	Mid to late June	37.7C at Lingwood, Norfolk (26 June)	New UK June record; a rare Met Office red extreme heat warning was issued for parts of central and southern England and Wales
Third heatwave	Early to mid July	35C in London (9 July)	Amber heat health alert covered London from 8 to 12 July
Possible fourth heatwave	Not yet confirmed	Not yet known	Met Office long range outlook hints at renewed heat by early August, but confidence is low

Is London expecting another heatwave right now?

No, London is not expecting a heatwave in the next few days. The Met Office’s update on 21 July says the coming days will be largely fine and dry, with warm sunny spells, especially in the south. That is pleasant summer weather, but it does not meet the heatwave threshold.

A UK heatwave is only declared when a location hits a set temperature threshold on three days in a row. For London, that threshold is 28C. Current forecasts have London staying below that mark for now, so no heat health alerts are in place at the moment.

This means it is a good window to enjoy the warm weather without the strain that came with June and July’s extreme spells. It is also a sensible time to prepare, since forecasters are already watching the next possible hot spell.

What does the Met Office forecast say for the rest of July?

The Met Office expects a mostly settled and warm stretch through the last week of July, followed by a more changeable period. Their long range forecast, covering 25 July to 18 August, describes a largely changeable spell with rain spreading southeast across the UK, mixed with sunny periods and showers.

That is not the setup for a heatwave. Rain and cloud tend to break up the kind of high pressure system that drives London’s hot spells. However, the same forecast notes that confidence gets lower the further ahead it looks, and there are hints that high pressure could return for a time. If that happens, dry conditions would resume, especially in the south, with temperatures near or above normal and possibly turning very warm again by the start of August.

In plain terms, this means the rest of July looks safe from extreme heat, but early August is worth watching. Forecasters cannot commit to a fourth heatwave yet, but they also have not ruled one out.

How many heatwaves has London had in 2026?

London has had three heatwaves so far in 2026. The first began on 22 May, when Kew Gardens hit 35.1C and broke the UK’s May temperature record by more than two degrees. The second struck in June, when a rare Met Office red extreme heat warning covered parts of central and southern England and Wales, with a UK June record of 37.7C recorded at Lingwood, Norfolk. The third arrived in early July, peaking at 35C in London on 9 July, with an amber heat health alert running from 8 to 12 July.

This means 2026 became the first year on record with UK temperatures reaching 35C or higher in May, June, and July of the same year. By 15 July, the year had already recorded more days above 30C than the whole of 1976, one of Britain’s most famous hot summers.

For anyone planning outdoor events, travel, or work in London, this track record is a useful reminder that hot spells this summer have been arriving roughly every three to five weeks, so keeping an eye on the Met Office’s updates through August makes sense.

Why has summer 2026 been so hot?

Summer 2026 has been hot because of repeated spells of high pressure building in from the south, combined with a warmer background climate. The Met Office reports that the UK’s average mean temperature for the summer so far is running 1.8C above the long term seasonal average, with minimum overnight temperatures 1.5C above average too.

High pressure systems block rain-bearing weather and let the sun heat the ground for days at a time. When that pattern lines up with warm air pulled up from the near continent, temperatures can climb quickly, as they did in May and June. Spring 2026 was already the warmest on record for England and Wales, which meant the ground and air were starting summer from a warmer baseline than usual.

Scientists also point to climate change as a background driver. Warmer average temperatures make record-breaking heat more likely and more frequent, which fits the pattern of three separate heatwaves and several broken national records in a single UK summer.

Humidity has also played a bigger role in 2026 than in some past hot summers. During June’s heatwave, dew points reached around 22C, much higher than the single figures recorded during the dry heat of the well known 2022 heatwave. High humidity matters because it slows down sweat evaporation, which is the body’s main way of cooling itself. That makes hot, humid days feel more draining and can raise health risks faster than dry heat at the same temperature, even for people who normally cope well with warm weather.

Overnight temperatures have added to the strain too. So called tropical nights, when the temperature stays above 20C after dark, make it harder for homes and bodies to cool down before the next hot day begins. The UK broke its overnight temperature record during the June heatwave, with 23.5C recorded at Cardiff Bute Park, showing just how little relief some areas got even after sunset.

What counts as a heatwave in London?

A heatwave in London is declared when the temperature reaches at least 28C on three days in a row. This threshold changes depending on where you are in the UK, ranging from 25C in cooler northern and western areas up to 28C across most of London and the southeast.

The Met Office uses this three-day rule because a single very hot day does not put the same strain on health, transport, and infrastructure as a sustained hot spell does. Alongside the weather threshold, the UK Health Security Agency runs a separate heat health alert system, colour coded yellow, amber, and red, which tracks the likely impact of heat on people and services rather than just the temperature itself.

Understanding this difference helps explain why you might see warm, sunny days in the news without an official heatwave being declared, and why an amber or red alert is a stronger signal to take precautions than the word heatwave alone.

It is also worth knowing that the threshold varies for a reason. A temperature that feels normal in the warmer southeast could be unusually extreme further north, where homes, infrastructure, and people are less used to sustained heat. By setting a lower bar in cooler regions, the Met Office can flag genuinely unusual conditions for that area rather than only reacting once London style temperatures appear everywhere.

How does London’s heat compare to the rest of the UK?

London usually runs a little hotter than most of the rest of the UK during a heatwave, though it is not always the single hottest spot on the map. In the June 2026 heatwave, the new national record of 37.7C was set at Lingwood in Norfolk, not in London itself, even though the capital also saw temperatures well into the mid-30s. This pattern is common because record highs often occur in East Anglia or parts of the southeast, where flat land and distance from the coast let heat build up.

Even so, London has its own extra source of heat: the urban heat island effect. Concrete, tarmac, and buildings soak up heat during the day and release it slowly overnight, which is why central London often stays several degrees warmer than surrounding countryside after dark. This is one reason the Met Office and UKHSA pay close attention to overnight temperatures in the capital, not just daytime highs, when deciding whether to issue a heat health alert.

For residents, this means London can feel hotter than the headline UK temperature suggests, especially at night. Homes without good airflow or shading can stay uncomfortably warm long after the sun goes down, which is worth keeping in mind if forecasters do confirm a fourth heatwave later in the summer.

How do you prepare for a possible heatwave in London?

You prepare for a possible London heatwave by checking the forecast regularly, keeping your home cool in advance, and having a plan for hot days before they arrive. Here is a simple step by step approach.

1. Check the Met Office forecast and UKHSA heat health alerts every few days through late July and August.
2. Close curtains and blinds on sun-facing windows during the day to keep rooms cooler.
3. Keep a supply of water at home and know your nearest free water refill point if you are out and about.
4. Identify cool spaces near you, such as libraries, shopping centres, or parks with shade, in case your home gets too warm.
5. Plan outdoor activities, exercise, or travel for the cooler parts of the day, generally before 11am or after 6pm.
6. Check in on elderly neighbours, young children, and anyone with health conditions if a heat health alert is issued.

Following these steps now means you will not be caught off guard if the Met Office’s early hints about renewed heat in August turn into a confirmed forecast.

FAQ

Will London have a heatwave this week?

No, London will not have a heatwave this week. The Met Office forecasts dry, warm, but not extreme conditions through 24 July.

Could London get a fourth heatwave in August 2026?

It is possible but not confirmed. The Met Office’s long range outlook hints that high pressure and warmer, drier conditions could return by early August, though confidence in this is currently low.

What temperature counts as a heatwave in London?

London needs three consecutive days of at least 28C to officially be in a heatwave. This is the highest threshold used anywhere in the UK.

How hot has it already been in London this summer?

London has already reached 35C twice in 2026, once in May at Kew Gardens and again in July, making this one of the hottest summers on record for the capital.

Where can I check the latest London heatwave forecast?

The Met Office website provides the most reliable daily and long range forecasts for London, along with any active UKHSA heat health alerts.

References

1. Met Office, “United Kingdom (National) weather” (2026)
2. Met Office, “Long-range forecast” (2026)
3. Met Office, “A largely settled period before another potential heatwave early next week” (2026)
4. Met Office, “Summer 2026 so far: A look at the season at the halfway point” (2026)
5. Met Office, “June 2026 heatwave: A recap of the temperature records” (2026)
6. Met Office, “Heatwave continues as UK records unprecedented run of 35C days” (2026)
7. Time Out London, “London Heatwave July 2026: Exactly How Hot It Will Get and When It Will End” (2026)
8. Wikipedia, “May 2026 United Kingdom heatwave” (2026)
9. Wikipedia, “2026 United Kingdom heatwaves” (2026)