Met Office Warns 'Tropical Nights' During This Week's Heatwave May Leave Millions Unable to Sleep

The Met Office has warned that millions could struggle to sleep this week as parts of England and Wales face several consecutive 'tropical nights', with temperatures expected to remain above 20C even after sunset.

The unusually warm nights are forecast to accompany a heatwave that could push daytime temperatures as high as 37C or 38C by midweek. Forecasters say the lack of overnight cooling may become one of the most significant aspects of the hot spell, preventing homes, buildings and city centres from shedding heat accumulated during the day and into the early hours.

Amber Extreme Heat Warnings are in place for much of England and Wales, with officials warning that consecutive hot days and persistently warm nights could increase health risks, place pressure on services and leave many people feeling exhausted as the week progresses. Yellow and Amber Heat Health Alerts have also been issued across parts of England.

'Tropical Nights' in Southern England

A tropical night occurs when temperatures do not fall below 20C after sunset. The Met Office said many parts of southern England could experience tropical nights particularly in towns and cities where concrete, roads and buildings absorb heat during the day and slowly release it overnight.

Deputy Chief Forecaster Tom Crabtree warned that several consecutive tropical nights could make it difficult for people to recover from the daytime heat. Extended periods of warm overnight temperatures can also disrupt sleep, leaving many people feeling tired as the heatwave continues.

Humidity is also expected to rise during the middle of the week. Forecasts suggest dew points could reach around 22C on Wednesday and Thursday, creating more humid conditions and making overnight temperatures feel warmer.

Temperatures Could Challenge June Record

Forecasters say the overnight temperatures may be just as important as the daytime highs. While heat records often focus on afternoon temperatures, tropical nights are less common in the UK and can affect large numbers of people across several consecutive days. Temperatures are expected to reach around 34C in parts of southern England on Monday before climbing further on Tuesday.

Current forecasts suggest highs of 37C could be recorded in southern England and around 35C in southeast Wales. The hottest conditions are expected on Wednesday and Thursday, when temperatures could reach 38C.

If those forecasts are realised, the UK's current June temperature record of 35.6C could be exceeded. That record was set in Southampton in 1976 and Camden Square in London in 1957.

Conditions are expected to remain cooler across parts of Scotland and Northern Ireland, where temperatures should stay closer to seasonal averages.

Health And Water Safety Alerts Issued

The UK Health Security Agency has issued Yellow and Amber Heat Health Alerts covering parts of England during the heatwave. Forecasters have also warned of isolated thunderstorms in parts of Devon and Cornwall early in the week, bringing the possibility of heavy downpours, lightning and gusty winds.

The Met Office said conditions should gradually begin to ease later in the week, although parts of eastern England could still reach around 33C by Friday.