Records illustrate the range of climate variability. With climate change, high temperatures are becoming more and more likely. The most extreme weather values recorded to date at the MeteoSwiss weather stations are detailed below for the parameters of temperature, precipitation, snow and wind.
The location of record-breaking events in Switzerland is heavily dependent on the topography, as this is what dictates the spatial distribution of temperature, precipitation and wind.
Generally speaking, the higher the altitude of a location, the colder it is. The coldest place in the MeteoSwiss observation network is the Jungfraujoch, at 3,571 m above sea level and an average annual temperature of -6.7°C. In valleys and hollows, cold air pools can form, where the temperatures dip especially low. The coldest temperature ever recorded in Switzerland (-41.8°C) was in just such a location, at the weather station in La Brévine, recorded in the winter of 1987.
In the low-lying areas, temperatures are higher. Particularly high temperatures are recorded in the canton of Ticino due to its deep valleys and southern location. The warmest location in Switzerland is Lugano with an average annual temperature of 13.0°C. The highest temperature recorded in Switzerland was from the very hot summer of 2003 at the weather station in Grono (GR) at the southern opening to the Misox (41.5°C). With climate change, new record temperatures are becoming increasingly likely.
The table below provides an overview of the record temperatures in Switzerland and compares them to European and global records.
| Switzerland | Europe | The world | |
|---|---|---|---|
| Lowest temperature | -41.8°C* *see Data basis below | Continental Europe: Incl. Middle East/Greenland: | -89.2°C |
| Coldest year | 1879 | No data | 1904 |
| Highest temperature | 41.5°C* *see Data basis below | 48.8°C | 56.7°C |
| Hottest year | 2022 | 2020 | 2023 |
The data on the hottest and coldest year on record relates to the average temperature for that year. The lowest and highest temperatures ever recorded in the named regions are one-off occurrences.
*The measurement series from La Brévine (minimum and maximum temperatures) was homogenised in 2011. In the process of doing so, it was found that the minimum temperature of -41.8 °C measured on 12 January 1987 would have been equivalent to -42.5 °C under today's measurement conditions. The difference is due to the transition, in October 1997, from the former manual system of measurements (in a measuring hut) to an automatic measuring system.
The weather station in Grono has been moved since the measurement was taken. Under today’s measurement conditions on the valley floor, the hottest temperature of the day would have registered as 40.5 C on 11 August 2003.
There are various data series that record the global temperatures dating back to the 19th century. The record-breaking data vary across the different data series, but the differences are small.
According to the University of East Anglia HADCRUT5 data series, 2016 was the warmest year on record globally since measurements began in 1850. The information on the coldest year globally (1904) also comes from this data series.
The figure for the hottest year in Europe comes from the Copernicus data series, which only goes back as far as 1979. It is therefore not helpful to look to this data series for the coldest year on record.
Long dry spells are already having an impact on agriculture and forestry, as well as shipping and other industries. Due to the decreases in summer precipitation, and because evaporation is increasing due to climate change, the problem of drought in summer will continue to become more pressing in the future. In the driest areas of Switzerland, snow and glacier melt are important water sources. The receding of the glaciers and expected snow deficits will place additional challenges on these areas in the future.
Mountains and valleys not only play a major role in determining temperature, they are also central to the distribution of precipitation. With an average annual precipitation of 543 mm in the 1991-2020 period, the driest place in the MeteoSwiss observation network is Stalden-Ackersand in the dry Visper valley in the canton of Valais. This is around half the amount of precipitation that falls in a year in central Switzerland. The longest uninterrupted dry phase was recorded in Lugano in 1988, with 77 consecutive days without precipitation.
Switzerland is in a moderate climate zone, and much longer dry periods have been recorded in other parts of the world. In the Chilean city of Arica, there were 172 months without precipitation between the years 1903 and 1918.
The wettest place in the MeteoSwiss observation network is Säntis, which sees 2,840 mm of precipitation in an average year. When a large amount of water falls from the sky in a short space of time, this increases the risk for landslides and flooding in a local area. The largest amounts of precipitation falling within a short space of time are normally seen in Ticino, where the southern orographic effect is responsible for large amounts of precipitation. In central Switzerland, heavy precipitation is mainly caused by thunderstorms. For this reason, the heaviest downpours occur primarily in the summer months.
Because warmer air can retain more water, climate change is contributing to the fact that heavy precipitation events are increasing. Records are one-off events, however. This is true for all weather parameters, but particularly for precipitation. A record-breaking weather event needs various factors to come together (including the weather situation at the time of the occurrence, the region of Switzerland in question, and the changes in weather over several days or weeks preceding the event). This is why some of the record precipitation events happened a long way back in the 20th century, in spite of climate change.
The table below provides an overview of record precipitation values in Switzerland, and compares them to records seen in the rest of the world.
| Highest volume of rain in | Switzerland | The world |
|---|---|---|
| 10 minutes | 41.0 mm | No data |
| 1 hour | 91.2 mm | 305.0 mm |
| 24 hours | 455 mm | 1,825 mm |
| 2 days | 612 mm | 2,493 mm |
| 3 days | 768 mm | 3,930 mm |
| 1 month | 1,239 mm | No data |
| 1 year | 4,173 mm | 26,470 mm |
The weather situation is the deciding factor for record-high snow amounts. In the central and eastern Alps, the largest amounts of snow fall mostly in connection with northern orographic effects or north-westerly flow. In the southern part of the alps, it is the southern orographic effects that bring the largest amounts of snow. Similarly to precipitation, the largest snowfall amounts have fallen in the past in the higher-altitude locations. With snow, a distinction is made between snowfall (fresh snow amount) and snow cover (snow depth). The deepest snow depth was recorded in April 1999 on Säntis, with 816 cm.
The table below gives an overview of other snow-related records.
| Greatest volume of snow in | ||
|---|---|---|
| 24 hours | 130 cm | 130 cm |
| 2 days | 215 cm | |
| 3 days | 229 cm | |
| 1 year | 2,073 cm |
In general, wind speeds tend to increase with altitude and distance from the earth’s surface. Close to the ground, the air circulation is slowed down by frictional forces. Particularly high wind speeds occur in Switzerland in deep depressions or in localised phenomena such as thunderstorms or foehn in the mountains. Due to the very localised character of thunderstorms, associated wind speeds are difficult to ascertain. Storms tend to occur in the winter months and can destroy large swathes of forest as well as infrastructure.
The highest wind speed recorded in Switzerland occurred in winter 1990 during storm Vivian, on the Great Saint Bernard pass. The table below gives an overview of the highest wind speeds recorded in Switzerland and the rest of the world.
| In the mountains | In the lowlands | Globally |
|---|---|---|
| Alps: Jura: | 190 km/h | 408 km/h |
No categorical prediction can be made regarding the effects of climate change on the future of winter storms with the currently available knowledge.