Switzerland is heading for another spell of summer-like weather, with temperatures expected to rise steadily through the week and reach about 30–32°C in parts of the lowlands by Friday, 4 September 2026, and over the weekend.
After a relatively mild start to September, temperatures are forecast to increase from around 25°C on Tuesday to approximately 26°C on Wednesday and 27–28°C on Thursday. The sharpest rise is expected from Friday, when highs of around 30°C or more are likely in several regions.
MeteoSwiss forecasts maximum temperatures of about 31°C on Friday and over the weekend in parts of Switzerland. SRF Meteo puts the upper range at 28–32°C, with the highest values likely in the Basel region, Geneva and Valais.
The warmest conditions are expected in the lowlands and western Switzerland, while the south may also reach around 32°C. Nights will remain noticeably cooler, limiting the classification of the spell as a formal heatwave.
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Switzerland’s Heatwave Threshold: Mostly Sunny And Dry
High pressure named “Thomas” is expected to dominate the weather pattern, bringing warm air from the Iberian Peninsula and largely dry conditions through Sunday. Forecasts point to plenty of sunshine, although high and mid-level cloud could pass through at times, particularly on Wednesday and Saturday.
Only isolated showers are expected, mainly in the mountains. A few showers or thunderstorms could develop overnight into Monday, but the extent of any rainfall remains uncertain.
Meteorologists say the late-summer heat could be unusual for the time of year. Lionel Fontannaz of MeteoSwiss described the first week of September as potentially “summery, even tropical,” with temperatures reaching or exceeding 30°C from Friday.
Several Swiss reports say September temperature records could be challenged if the current forecast pattern holds, although meteorologists caution that it is still too early to predict records with confidence.
For Now, Meteorological Autumn Is Unlikely To Feel Particularly Autumnal
Temperatures are expected to ease slightly to around 27–30°C early next week, with hot days becoming more localised. A more noticeable return to seasonal conditions could arrive around the middle of next week, when highs near 20°C are possible.
For now, however, the beginning of meteorological autumn is unlikely to feel particularly autumnal: Switzerland is set for another sunny, dry and unusually warm stretch, with the hottest days still ahead.
