Switzerland issues highest heat warning for Basel as country braces for 37°C heatwave
The Swiss government has activated heat alerts across much of the country, with the Basel region placed under the most severe warning as temperatures are forecast to climb to 37°C.
The Federal Office of Meteorology and Climatology (MeteoSwiss) issued the warnings on Wednesday 17 June, covering a period from Thursday noon until Tuesday 20:00. Most of the Swiss Plateau, eastern and central Switzerland, the Grisons, Romandy, large parts of Valais, and Ticino fall under alert level 3 of 4, denoting "significant" risk. The highest level, 4, currently applies to the cantons of Basel-Stadt and Basel-Land, where the danger is deemed "high".
Temperature trajectory
Daytime highs will climb steadily through the weekend. According to MeteoSwiss, temperatures are expected to reach 32–34°C on Friday, 33–36°C on Saturday, and 34–38°C by Monday. The hottest stretch runs from Sunday midday through Tuesday evening. A spell of thunderstorms on Friday may bring temporary relief.
What the warnings mean
Level 4 is declared when the mean daily temperature stays at or above 27°C for at least three consecutive days; level 3 kicks in at 25°C over the same period. The alerts apply to areas below 800 metres above sea level. Authorities stress that heat represents a serious threat to people, animals, the environment and infrastructure, with a high risk of circulatory problems and physical discomfort for vulnerable groups.
Official advice
Residents are urged to drink plenty of fluids (at least 1.5 litres a day of unsweetened, non-alcoholic drinks), seek shade, and avoid strenuous activity during the hottest hours. People and animals must never be left inside a parked car.
Escaping the heat
Those looking to cool down are turning to higher ground and water. Roger Perret, a meteorologist at Meteo News, noted that even at 4000 metres the temperature hovers around zero, while at around 2000 metres it reaches approximately 20°C.
Small lakes have already warmed to about 25°C, while large lakes remain 2–3°C cooler than usual. Mountain lakes in the Upper Engadine offer a brisk 13–14°C. Hiking destinations such as the Rigi (expected to reach a pleasant 20°C at the weekend) and the Chasseral in the Jura (around 25°C) are recommended.As far as the eye can see, it’s hot.
- Heat warnings take effect: level 3 for most of the country, level 4 for Basel region.
- Thunderstorms expected, possibly easing the heat temporarily.
- Daytime highs of 33–36°C; continued level 3/4 alerts.
- Hottest phase begins, with temperatures reaching 34–38°C by Monday.
- Heat warnings set to expire.
