On a sweltering Monday morning, the Met Office issues an amber extreme heat warning—a rare alert that signals temperatures could soar to 35°C, threatening the health of millions and disrupting travel across southern England and Wales. These warnings, first introduced in July 2021, are reserved for the most impactful heat events and have only been issued six times since their creation.
An amber extreme heat warning is a Met Office alert that covers parts of England and Wales, warning that temperatures are expected to reach levels that can affect the general population—not just the most vulnerable. The warning is separate from the amber and yellow heat-health alerts issued by the UK Health Security Agency (UKHSA), which focus on impacts on health and social care services. For example, the UKHSA amber alert warns of a likely increase in deaths among elderly and vulnerable people, while the Met Office's amber warning indicates that even healthy individuals may experience heat exhaustion, sunburn, and travel disruption.
“What amber extreme heat warnings are, how they work, and why they matter for UK readers.”
The Met Office introduced amber extreme heat warnings in July 2021, and the most recent one before this event was in August 2022. A more severe red warning was also issued in July 2022. The current warning, valid for Monday and Tuesday, covers parts of southern and eastern England and south Wales, with temperatures peaking at 34–35°C. Overnight temperatures may remain above 20°C in some areas, providing little relief.
For UK readers, these warnings have practical implications. They mean that travel delays are likely on roads and railways, particularly in London where Tube and rail services may be disrupted. They also urge caution around water: the Royal National Lifeboat Institution warns that open water remains cold enough year-round to trigger cold water shock, which can cause drowning. People are advised to enter water slowly and ‘float to live’ if in danger. Additionally, while solar panels can still generate electricity during heatwaves, their efficiency drops slightly above 25°C; a hot but hazy day may produce less power than a cooler, clear day.
Key questions answered: Q: What is the difference between a Met Office extreme heat warning and a UKHSA heat-health alert? The Met Office amber warning focuses on impacts on the general population, including travel disruption and health risks like heat exhaustion. The UKHSA amber alert specifically warns of significant impacts on health and social care services, with a likely increase in deaths among elderly and vulnerable people.
Q: How hot does it need to be for an amber extreme heat warning? Temperatures typically peak at 34–35°C (93–95°F) during such warnings, and the UK's June record of 35.6°C (96.1°F) set in 1957 and 1976 could be broken. Nights may stay above 20°C.
Q: Do solar panels work better in a heatwave? No. Solar panels need sunlight, not heat. High temperatures can slightly reduce their efficiency because voltage drops as the panel heats up. However, for most UK households, the drop is modest and bright sunshine can still deliver strong generation.
What happens next: The amber warning covers Monday and Tuesday, with temperatures peaking on those days. There is a chance the June temperature record could be broken. Thunderstorms are possible in some areas, which could bring localised disruption. Scotland and Northern Ireland will remain cooler.