Forecasters are predicting another long hot spell for London and the South East starting this weekend.
The capital will bask in a nine-day heatwave starting on Saturday with temperature highs of at least 28C, according to BBC Weather’s latest two-week forecast on Thursday (July 2).
If the prediction proves correct, it will see London enveloped in a second heatwave in just three weeks.
A high of 36.4C was recorded at Heathrow on Friday, June 26, beating the previous London June record of 35.6C in Camden in 1957.
The same day, 37.7C was recorded in Lingwood in Norfolk - a UK June temperature record - according to the Met Office.
The cause of the latest anticipated heatwave is an area of high pressure centred over the subtropical Atlantic.
The so-called Azores High is expanding towards the UK, drawing hot air up from the south and keeping Atlantic storm systems at bay.
On Wednesday, health officials issued a warning for hot weather in parts of the UK, saying high temperatures over the coming days could cause a greater risk to life for vulnerable people.
An impressive return to #heatwave conditions on the latest EC op! 🤯
— WXCharts - a MetDesk Company (@wxcharts) July 2, 2026
Do you believe these levels, or do you think they are too high?
Note this is a #temperature anomaly map. pic.twitter.com/wYKNg5IwQx
The yellow heat health alert has been issued by the UK Health Security Agency (UKHSA), covering the East Midlands, east, south-east and south-west England, including London, from 12pm on Saturday, July 4, until 5pm on Wednesday, July 8.
The agency said that within the warning area, minor impacts were likely across health and social care services because of the high temperatures, including increased use of healthcare services by vulnerable people and a greater risk to life to the same group.
It also warned of a potential increase in water-related incidents, including risks from cold water shock and drowning.
Allergy UK warned people living with asthma or hay fever could experience “thunderstorm asthma”, which occurs when thundery weather causes high winds to bring pollen and pollution into the atmosphere, which can then be inhaled deep into the lungs, triggering or worsening asthma symptoms.
Amena Warner, head of clinical services at Allergy UK, said: “Most people with hay fever will experience their normal range of symptoms – sneezing, runny nose and itchy eyes, but these will be more extreme.
“However, more worryingly, hay fever can cause asthma symptoms to worsen and thunderstorm conditions can cause even mild symptoms to become severe, such as difficulty breathing and chest tightening.
“For anyone affected by asthma and hay fever, it’s important to be prepared and diligent in taking allergy treatments and medications to manage symptoms.
“Anyone who experiences difficulty breathing should seek medical help without delay.”
The charity said people can reduce the risks related to thunderstorm asthma by staying indoors before, during and after the storm, wearing a mask when outdoors to reduce pollen exposure, taking their usual medication, keeping a reliever inhaler with them and monitoring their asthma in case it deteriorates.
