Zero-degree line climbs to record level

The highest point in Switzerland is the Dufourspitze (Dufour Peak) at 4,634 metres. Keystone / Martin Ruetschi

The current hot spell has pushed the zero-degree line – the height at which the temperature goes into the minus – far above the highest Alpine peak. On Sunday night it reached 5,184 metres above sea level, a new record.

This content was published on July 25, 2022

The old record, 5,117 metres, dates back to 1995, according to MeteoSwissExternal link and Meteonews. The highest point in Switzerland is the Dufourspitze (Dufour Peak) at 4,634 metres.

The zero-degree line is determined by meteorologists using weather balloons which take off twice a day from Payerne in western Switzerland.

"This situation is due to warm air currents coming from the south-southwest, from North Africa and the Iberian Peninsula," Vincent Davantay of MeteoNews told Swiss public radio, RTS.

"This creates fears of instability of the rocky and glacial masses at high altitude, with falls of glacial ice and landslides, especially as there hasn't been much snow this winter."

Record-breaking month?

MeteoSwiss, the federal meteorology and climatology office, said the new record and the old one from 1995 are the only values ever measured above 5,000 metres. A reading of 4,900 metres would already guarantee a place in the top ten.

The office added that when it came to the zero-degree line, this July could see the highest monthly average of daily maximums. The current record average (4,325 metres) was registered in July 2015; so far this month the average is just over 4,260 metres.

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