Met Office warns of 35C heat and tropical nights as UK heatwave warning widens

The Met Office has widened its amber extreme heat warning as parts of the UK brace for temperatures forecast to peak at about 35C next week, with forecasters warning that some areas could also see so-called tropical nights.

The warning was first issued on June 19 for much of southern England and south-east Wales. By June 20, reporting said it had been expanded to include eastern Wales and much of the Midlands, as the hottest period came into focus for Monday and Tuesday.

What the warning covers

Temperatures are expected to climb to around 30C over the weekend before rising further early next week. The latest forecasts put highs at about 34C on Monday and Tuesday, with some reporting saying 35C could be reached in parts of the country.

The Met Office has also warned that cloudy conditions and high humidity could make the heat feel rather oppressive. Isolated thunderstorms are possible as well, adding a further element of disruption for travel and outdoor plans.

The UK Health Security Agency has issued amber heat-health alerts for eastern England, London, the south-east and the south-west, with yellow alerts in parts of the Midlands. The alerts are intended to flag increased pressure on health and care services during the hot spell.

Why the nights matter

The phrase tropical nights refers to overnight temperatures that do not fall below 20C. Those warm nights matter because they give people less chance to cool down after hot daytime temperatures.

That can be particularly important for older adults and people with existing health conditions, who are more vulnerable to dehydration, heat stress and the effects of poor sleep when nights stay very warm.

Timeline of the heatwave

The developing heatwave has been building over several days. Reporting on June 18 said amber heat warnings were already in place across parts of southern England, with temperatures expected to rise through the weekend.

On June 19, the Met Office warning was described as a rare amber extreme heat warning for parts of England and Wales, with London and other areas already under UKHSA heat-health alerts.

By June 20, the forecast had sharpened further, with coverage saying the amber warning had broadened and that the peak heat could reach 35C next week. That same reporting also said tropical nights were likely in some areas.

Health and safety risks

The main concern is not only the daytime temperature but the combination of heat, humidity and limited overnight relief. That can make the period harder to manage for people who are already unwell, socially isolated or caring for others.

Health services can also come under strain when hot weather is prolonged. The amber alerts are meant to help health and care systems prepare for higher demand, while households are urged to pay attention to vulnerable relatives, neighbours and patients.

Open-water safety is another issue during hot spells. The Royal National Lifeboat Institution has repeatedly warned that cold-water shock and drowning remain serious risks for swimmers, even when air temperatures are high and the water may look tempting.

Record watch

The heat has also raised the question of whether the UK could challenge its June temperature record of 35.6C. Reporting differs on the year attached to that figure: The Guardian said it was set in 1957 and 1976, while The Sun said 1975.

For now, the key verified development is the widening of the amber warning and the forecast for a multi-day spell of severe heat, humid nights and public-health concern across a broad stretch of England and Wales.

Forecasters will now be watching whether temperatures reach 35C, whether the warning is extended beyond Tuesday and whether UKHSA keeps its alerts in place if the hot spell persists.