A Swiss weather balloon had to climb to an unprecedented 5,300 metres (17,400ft) before the temperature fell to 0C (32F), meteorologists have said, as a late summer heatwave and wildfires continue to pummel swaths of continental Europe.
A man was found dead in a blaze raging north of Athens on Monday as the Greek government warned of an extreme risk of fire across the country, while more than half of mainland France was placed under an amber extreme heat alert and local records tumbled in the south-east.
MétéoSuisse said the zero-degree line – the altitude at which the temperature falls below freezing, considered a key meteorological marker particularly in mountainous regions – was measured at 5,298 metres overnight.
The figure, which was registered by a weather balloon flown from Payerne in western Switzerland, constituted “a record since monitoring began in 1954”, the service said, and surpassed the previous high of 5,184 metres that was “only set in July last year”.
Le radionsondage de Payerne de cette nuit du 20 au 21 août 2023 a mesuré l'isotherme du 0 °C à 5298 m ce qui constitue un record depuis le début des mesures en 1954. Le précédent #record datait seulement du 25 juillet de l'année dernière avec 5184 m. #meteosuisse #canicule pic.twitter.com/dWjnKIRQ7r
— MétéoSuisse (@meteosuisse) August 21, 2023“,”url”:”https://twitter.com/meteosuisse/status/1693469967855845552″,”id”:”1693469967855845552″,”hasMedia”:false,”role”:”inline”,”isThirdPartyTracking”:false,”source”:”Twitter”,”elementId”:”8f4f3775-9582-4cee-bff4-b84d83f5da03″}}”>
The 0C line “affects vegetation, the snow line and the water cyc
