Met Office warns of ‘tropical nights’ in Wales that will make it hard for people to sleep

The Met Office has warned parts of Wales could experience “tropical nights” this week, with overnight temperatures staying above 20C

People across Wales are being warned to prepare for uncomfortable nights as temperatures remain unusually high after sunset during this week’s heatwave. The Met Office says parts of Wales could experience what meteorologists call “tropical nights” – when temperatures fail to drop below 20C overnight.

While much of the focus has been on soaring daytime temperatures, forecasters have warned that the lack of overnight relief could significantly increase the health impacts of the heatwave.

Met Office deputy chief forecaster Tom Crabtree said: “As well as very high daytime temperatures, there will be consecutive nights where temperatures do not drop below 20°C, which is called a Tropical Night.

“This will make it very hard for people to recover from the daytime heat, exacerbating the heat stress impacts.” Make sure you never miss Wales’ biggest updates by getting our daily newsletter.

The warning comes as temperatures across Wales are forecast to climb well above 35C in many areas this week, with some locations potentially approaching the high 38C mark.

Health experts say overnight cooling is vital during periods of extreme heat, allowing the body to recover from hot daytime conditions. When temperatures remain elevated through the night, the risk of heat-related illness increases, particularly for older people, young children and those with underlying health conditions.

The Met Office has warned that the prolonged spell of heat could have impacts across the wider population, with sleep disruption expected to affect many people even if they are otherwise healthy.

Warm, humid conditions are expected to make bedrooms feel particularly uncomfortable, especially in urban areas where buildings and roads retain heat long after sunset.

Forecasters say some locations may not fall below 20C or 21C for several consecutive nights, creating conditions more commonly associated with Mediterranean destinations than Wales.

The combination of exceptionally hot days and tropical nights has prompted the Met Office to issue amber heat warnings covering large parts of Wales, with officials urging people to stay hydrated, keep homes as cool as possible and check on vulnerable friends, relatives and neighbours.

The hot weather is expected to continue until at least Thursday, although there are signs that cooler Atlantic air could begin moving in from the west later in the week.

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