Together with 2019/2020, mildest winter since start of measurements!

The following is an overview of the weather during yesterday's meteorological winter (December to February) in terms of temperature, precipitation and sunshine duration. For details of the individual months, please refer to the monthly balance sheets for December, January and February.

Record mild with a temperature surplus of around 2.7 degrees

The meteorological winter of 2023/2024 was around 2.7 degrees too mild across Switzerland compared to the climate norm from 1991 to 2020 and, together with the winter of 2019/2020, was the mildest winter since measurements began in 1864 (see Fig. 1). The range extends from 2.1 degrees on the Jungfraujoch to 3.7 degrees in La Brévine. Among the individual months, the temperature surplus was greatest in February at around 4.7 degrees, making it by far the mildest February since measurements began. But December and January were also too mild, December 2 degrees (fifth mildest December since 1864) and January 1.4 degrees (at some measuring stations one of the mildest Januarys since records began).

Quite widely too wet, sometimes significantly

In terms of precipitation, last winter ended with a surplus in many places, amounting to around 37% across Switzerland as a whole (see Fig. 2). Locally, there was even more than twice as much precipitation as normal, especially in parts of southern Grisons. December and January were too wet, with an excess of around 82% in December (locally the wettest December since records began) and 17% in January (too wet in the north). By contrast, February was 2% too dry (too wet in the south, too dry in many places in the north).

Snowy at high altitudes

After a snowy start, even for the swiss plateau, at the beginning of December, the snow line repeatedly retreated to higher altitudes above 1500 m over the course of the winter, with the exception of the first half of January. Due to the wet conditions, there is currently often an average to above-average amount of snow above around 2000 m, while the amount of snow is significantly below average, especially below around 1500 m (see Figs. 3 and 4).

Too little sun

Last winter, the sun shone around 10% less frequently than normal across the whole of Switzerland (see Fig. 5). There was significantly too little sunshine in the Alps and the Jura in particular, while the Central Plateau and Lake Geneva were a little too sunny in places. All three winter months were too cloudy, although the deficit was only 3 to 4% in December and January and around 18% in February. February was therefore mainly responsible for the winter deficit in sunshine.