On Wednesday, temperatures across parts of England are forecast to hit 35°C—hot enough to trigger amber heat-health alerts and warnings of increased deaths among the elderly and vulnerable. The UK is in the grip of its fourth widespread heatwave of the year, and the government’s health agency is telling hospitals and care homes to prepare for a surge in admissions. But what exactly is a heatwave in the UK, and why do these alerts matter?
The Met Office defines a heatwave as when a location records at least three consecutive days with temperatures above a threshold—usually 25°C for most of the UK, though it varies by region. Wednesday is expected to be the hottest day of this spell, with the mercury reaching 30-35°C across southern and eastern England, the East Midlands, and parts of Wales. The heat is being driven by a plume of hot air from North Africa, which has already pushed temperatures to extreme levels in Iberia and France.
“What UK heat-health alerts mean as temperatures hit 35°C during a fourth heatwave.”
In response, the UK Health Security Agency (UKHSA) has issued amber heat-health alerts for the East Midlands, East of England, London, and South East from 09:00 BST on 29 July to 09:00 BST on 30 July. Yellow alerts are also in place for the South West, West Midlands, and Yorkshire & the Humber. Amber means significant impacts are likely across health and social care services, including a rise in deaths, particularly among those aged 65 and over or with pre-existing conditions. The alerts are designed to give the NHS and local authorities time to put extra measures in place, such as checking on vulnerable people and ensuring cooling facilities are available.
These heatwaves are not new. The UK has seen a series of hot spells this summer, and the lack of rainfall has left ground dry and soil moisture low, raising the risk of wildfires. Firefighters in the Cairngorms recently battled a blaze for at least 10 days, and more than 200 wildfires have been recorded in the last fortnight. Across Europe, hundreds of thousands of people have been evacuated from their homes due to fires, with France calling it its most difficult situation since the Second World War.
For UK readers, the practical impact is immediate. If you live in an area covered by an amber alert, you should check on elderly neighbours, avoid going out during the hottest part of the day, and keep homes cool. The heat will be short-lived—temperatures are expected to drop by 5-8°C on Thursday as a weather front brings fresher air—but the risk to health is real. Even after the peak, it will remain warm, with mid-to-high 20s persisting into the weekend. And with no significant rain forecast for the driest regions, the wildfire danger will stay elevated.
Q: Are there hosepipe bans in place? Several water companies have introduced temporary use bans (hosepipe bans) in parts of England due to the prolonged dry weather. Check your local water provider’s website for the latest restrictions in your area.
Q: How long will this heatwave last? The hottest conditions are concentrated on Wednesday. By Thursday, a weather front will bring cooler, fresher air, dropping temperatures by about 5-8°C. However, it will still be warm, with mid-to-high 20s Celsius expected into the weekend.
Q: What is the difference between amber and yellow heat-health alerts? An amber alert means significant impacts are likely across health and social care, including a rise in deaths among vulnerable groups. A yellow alert indicates less severe impacts but still requires awareness and preparedness.
What happens next? The heatwave will ease quickly, but the underlying dry conditions mean the risk of wildfires remains elevated. The Met Office and UKHSA will continue to monitor temperatures and issue updates. For now, the focus is on protecting the most vulnerable during the hottest day, and then assessing the damage to crops, water supplies, and natural habitats as the summer continues.
