UK heatwave June 2026: Red extreme heat warning issued and record-breaking temperatures predicted

Last updated: 22 June 2026

The Met Office has issued a rare red extreme heat weather warning for later this week. Temperatures in parts of England and Wales are forecast to reach 38ºC on Wednesday 24 and Thursday 25 June, as the UK experiences the second official heatwave of the year.

Red warnings are the highest alert level, reserved for situations with a risk to life and major disruption. It follows the amber and yellow heat-health alerts issued by the UK Health Security Agency on 22 June 2026. 

Met Office Deputy Chief Forecaster Mark Sidaway, said: “Red warnings are reserved for the most severe events and we’re expecting severe and significant impacts from this heatwave, with health impacts likely for many, even beyond those who are normally more vulnerable to the heat. The last time the UK recorded temperatures this high was in July 2022, but on this occasion the heat is expected to be accompanied by high humidity.  

“As well as very high daytime temperatures, there will be consecutive nights where temperatures do not drop below 20°C, which is called a Tropical Night. This will make it very hard for people to recover from the daytime heat, exacerbating the heat stress impacts.” 

The Red heat warning is in place from 9:00am on Wednesday morning to 9:00pm on Thursday evening. Amber heat warnings are also in place on Monday 22 and Tuesday 23 of June.

Find out whether your area is affected: Met Office UK weather warnings

Record breaking temperatures

The Met Office predicts that this heatwave will break several records including: 

• UK June temperature record
  • Current record: 35.6°C
  • Locations: Southampton (1976) and Camden Square, London (1957)
  • Status: Very likely to be broken
• Wales June temperature record
  • Current record: 33.7°C
  • Set in: 2000
  • Status: Likely to be broken 

The highest ever recorded temperature in the UK was in Coningsby, Lincolnshire on 19 July 2022 when temperatures reached 40.3C.

What does an red extreme heat weather warning mean?

According to the Met Office a "red alert would indicate significant risk to life for even the healthy population", with "severe impacts would be expected across all sectors with a coordinated response essential."

A red extreme heat weather warning is the highest alert level and could mean: 

• population-wide adverse health effects experienced, not limited to those most vulnerable to extreme heat, leading to serious illness or danger to life
• substantial changes in working practices and daily routines will be required
• high risk of failure of heat-sensitive systems and equipment, with the loss of power and other essential services, such as water, electricity, gas or mobile phone services
• significantly more people visiting coastal areas, lakes and rivers, leading to an increased risk of water safety incidents
• delays on roads and road closures, along with delays and cancellations to rail and air travel, with significant welfare issues for those who experience even moderate delays

Make sure you are prepared with our heatwave advice.

Will there be a heatwave?

A heatwave is declared in the UK when a location records at least three consecutive days with temperatures exceeding the threshold for that location. The threshold for most of the north and north-west of England is 25ºC, but for London and the Home Counties, it is 28ºC.

The Met Office predicts that heatwave thresholds could be reached across parts of the UK for the second time this year in June 2026.

What is a heatwave? 

How to prepare for periods of hot weather

It’s important to know how to prepare and stay safe during extended periods of hot weather.

William Spencer, climate and first aid product manager at the British Red Cross, said: “It’s important to take care while you have fun with friends and family and avoid getting sunburn, heat stroke or becoming dehydrated. 

“Higher temperatures can make it harder for the body to cool itself and we all need to take care to manage the health risks of heat. There are several steps you can take to keep yourself and others safe.  

“We would advise people to make sure they know how to recognise the symptoms of heat exhaustion and heat stroke and avoid activities in the middle of the day when temperatures are highest.  

“Other safety tips include wearing sunscreen, drinking plenty of water and drinking less alcohol. You can also help keep your home cool by keeping blinds and windows closed during the hottest parts of the day.”

Resources to help you stay safe:

• How to prepare for a heatwave
• Top tips to stay cool in hot weather
• How to keep your home cool in a heatwave
• How to keep cool at night
• How to prevent your home from overheating 

Hot weather will affect people in different ways and there are certain groups who are more at risk than others.

If you are a member of a vulnerable group or know someone who is likely to be more affected by a heatwave or hot weather, it’s important you are prepared for how to cope in a heatwave.