What is a tropical night? London swelters in record overnight heat for May

London experienced its first tropical night of the year on Monday, with temperatures at Kenley Airfield in south London not falling below 21.3C overnight. The Met Office confirmed this marked a tropical night, defined as a night where temperatures stay above 20C. Earlier in the day, Kew Gardens recorded the UK’s highest-ever May temperature at 34.8C, with forecasts predicting further heat, potentially reaching 36C in the city on Tuesday. Tropical nights, once rare in the UK, are becoming more common due to climate change, according to the Met Office. The UK saw three consecutive tropical nights in 2022, a milestone that studies suggest is increasingly likely, now with a 20% annual probability. High nighttime temperatures are linked to increased mortality, particularly among older adults and those with pre-existing health conditions, as the body struggles to regulate temperature in poorly ventilated homes. The Met Office warns that extreme heat events will worsen, requiring urgent adaptation strategies, such as improving building ventilation and supporting vulnerable communities. Only 5% of UK homes have air conditioning, leaving many reliant on creative cooling methods like fans, light bedding, and open windows to stay comfortable. Experts advise avoiding alcohol, caffeine, and cold showers before bed, as these can disrupt sleep during heatwaves. Sleeping on damp towels or using cold water bottles may also help, though waking to cool down in a different location may be necessary if sweating disrupts rest. The UK must prepare for more frequent tropical nights, as climate change accelerates extreme weather patterns.