Meteorological autumn (September to November) is coming to an end, it is time to take stock. The fall of 2024 was about 1.2 degrees too mild compared to the multi-year average, making it the seventh mildest fall since 1864. It was significantly too mild, particularly in the mountains. Throughout Switzerland, it was also a little too humid (especially in the north) and too cloudy (especially on the Plateau).
Just over a degree too mild
The fall of 2024, which is ending soon, was too soft by about 1.2 degrees throughout Switzerland, which places it at the seventh rank mildest autumns since measurements began in 1864. The positive temperature difference in the mountains (locally up to more than 1.5 degrees) was greater than in the plains where the excess temperature was often slightly lower at 1 degree. Maximum and minimum temperatures contributed approximately equally to this excess.
Fig. 1: Temperature deviation in fall 2024 compared to the 1991-2020 climate average; Source: MeteoNews, UBIMET
The months of October (2 degrees too mild) and November (1.6 degrees too mild) were mainly responsible for this excess, while the month of September was a little cooler than normal (0.2 degree).
A little too humid
Regarding precipitation, we see a excess of just over 15% throughout Switzerland. While in the north, with the exception of Graubünden, it was a little too wet in many places, in Ticino it was a little too dry in most places.
Fig. 2: Precipitation deviation in autumn 2024 compared to the 1991-2020 climate average; Source: MeteoNews, UBIMET
There were big differences depending on the month: September was clearly too wet (around 50%), October a little too wet (almost 20%) and November a little too dry (around 20%).
A little too cloudy
Throughout Switzerland, the sun shone about 13% less than normal last fall. It was particularly cloudy on the Plateau, while the deficit is generally only very small in the mountains, in the Jura, in the south of Ticino and sometimes in the Alpine valleys.
Fig. 3: Difference in sunshine duration in autumn 2024 compared to the 1991-2020 climate average; Source: MeteoNews, UBIMET
If we consider the different autumn months, we see that September (by 25%) and October (by 33%) were clearly too cloudy. The situation is different in November, where the sun shone almost 45% more often than normal, with the differences being even greater in the mountains.
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