Red extreme heat warning extended in Sussex and Surrey as UK faces historic three-day alert
The Met Office has extended its red extreme heat warning across the UK, including Sussex and Surrey.
It is the first time in the history of the UK’s current weather warning system, that red-level alerts for extreme heat have been issued for three consecutive days.
The government agency warned that the intense and prolonged heatwave will continue to grip large parts of England, with dangerous temperatures and high humidity expected to persist into Friday (June 26).
The extension means that some of the highest-level heat alerts in the UK weather warning system remain in force for a longer period than initially forecast, affecting millions of people across London, the Home Counties, and the South East.
The initial alert, for Wednesday and Thursday, covered parts of northern and eastern Sussex, including Crawley, Horsham, Billingshurst, Petworth, Haywards Heath, Uckfield and Crowborough. This was later expanded to include Chichester, Arundel, Worthing and Brighton.
On Friday, the alert covers the majority of Sussex, except the Chichester & Arun districts, as well as Worthing and surrounding areas.
Professor Stephen Belcher CBE, Met Office chief scientist, said: “The heatwave this week is a significant weather event, with a Red Extreme Heat warning issued. Human induced climate change has made events like this more likely and more intense.
“To see temperatures like this in the UK in June is sobering. Events like this bring home the implications of climate change, with very high temperatures and humidity bringing significant health implications from heat stress, as well as impacts to a range of sectors such as transport, energy and water supply.”
Alongside the heat, a yellow thunderstorm warning is in place for parts of the UK on Friday morning. However, forecasters confirm that Sussex and Surrey are not included in the thunderstorm warning area.
The storms are expected to bring the risk of heavy rain, lightning, and localised disruption in some regions, although the highest impacts are expected elsewhere.
Forecasters say temperatures are still expected to reach 36°C to 37°C widely, with isolated areas potentially seeing even higher values. Officials also warn that high humidity will intensify the impact of the heat, creating oppressive conditions both day and night and limiting the body’s ability to recover after prolonged exposure.
The Met Office said the persistence of the heatwave represents an ‘exceptional spell of hot and humid weather’, with conditions remaining hazardous despite slight regional shifts in peak temperatures. Overnight temperatures are expected to stay unusually high, adding to cumulative health risks.
The extended warning signals continued disruption to everyday life. Transport services may face delays and restrictions, while infrastructure such as roads and railways remains under strain from sustained heat. Authorities have also cautioned that essential services, including electricity and water supplies, could experience additional pressure in some areas.
Health officials are warning that the risk of heat-related illness now extends across the general population, not just vulnerable groups. Prolonged exposure, combined with warm nights, increases the likelihood of exhaustion, dehydration, and other serious heat-related conditions.
Public spaces, particularly parks, rivers, lakes, and coastal areas, are expected to remain extremely busy, raising ongoing concerns around water safety and emergency incidents. People are being urged to avoid unnecessary travel during peak hours, stay hydrated, and take extra care with those most at risk.
Officials continue to advise simple protective measures, including staying out of direct sun during the hottest part of the day, keeping indoor spaces cool, and checking regularly on elderly or vulnerable individuals.
The UK Health Security Agency has also issued a series of heat health alerts, which specifically highlight the potential health and social care impacts.
Dr Agostinho Sousa, head of extreme events and health protection at UKHSA said: “Very hot weather is forecast across large parts of England in the coming days and we are urging health and social care services across the country to ensure they are prepared. It is vitally important that people understand the risk posed by high temperatures like these, and take steps to keep themselves and their friends, families and neighbours safe.
“A red heat health alert indicates a risk to life for even the healthy population, but simple actions like staying hydrated, avoiding the sun during the hottest part of the day, and keeping your home cool can make a big difference. It’s also important to look out for others, especially elderly relatives, neighbours, and those with underlying health conditions, to make sure they are aware of the forecast and following the necessary advice.”
The extension of the red warning highlights the unusual severity and duration of the current heatwave, which meteorologists say is placing sustained pressure on both public health and infrastructure across southern England.