The Met Office has explained what tropical nights are as the UK braces for a heatwave that could break weather records. A heat dome settling over western Europe is expected to push temperatures up to 40°C in parts of the UK by Wednesday.
What are tropical nights?
A night is classified as tropical when the temperature does not drop below 20°C. This phenomenon is set to occur across parts of England and Wales, particularly in urban areas, as the heatwave intensifies.
Weather warnings and temperature forecasts
Weather warnings for extreme heat have been issued for many parts of the UK this week. The North East has an amber alert, while a red warning, running until the end of Thursday, covers much of southern and central England as well as Wales. In the North East, temperatures are predicted to reach 29°C on Tuesday and remain in the high 20s for the rest of the week. Meanwhile, southern areas could hit 40°C.
Overnight temperatures and humidity
It won't just be hot during the day. Overnight temperatures will also be high, with widespread tropical nights. For example, in Newcastle, the temperature at 11pm on Tuesday, June 23, is forecast to be 22°C, dropping just below 20°C to 19°C at 2am, with the lowest overnight temperature at 17°C. On Monday night, the highest overnight temperature was 20.4°C in Gosport, Hampshire, while eight other locations recorded tropical nights: Crosby in Merseyside, Plymouth and North Wyke in Devon, Aberporth, Cardiff and St Athan in Wales, Hurn in Dorset, and the Isle of Wight.
Humidity adds to the impact
The Met Office added: "Humidity is also a factor, making this heatwave even more impactful with heat stress a danger to all. Dew points, which indicate how humid the air is, are forecast to reach around 22°C in places on Wednesday and Thursday. For comparison, during the record breaking July 2022 heatwave they were widely lower, highlighting how oppressive this heatwave will be."
