Weather in Basel for September 2025
Until now, September 2025 in Basel is cooler than usual, with temperatures averaging 20.2 °C, this is -4.2 °C below the typical seasonal average.
Expect cooler weather in the next days in Basel with the forecast suggesting a temperature of 21.5 °C, lower than the historical average.
In general, the average temperature in Basel at the beginning of September is 25.6 °C. As the month progressed, temperatures tended to significantly cool down, reaching an average of 18.9 °C by the end of September.
Basel experiences heavy rainfall in September, with over 20 rainy days and an average total precipitation 75.2 mm.
Temperatures
Rain 🌧️
Basel Weather September
Temperatures trend during September in Basel
September weather in Basel day by day
| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| 1 Sept. |  Cloudy | 24° /12° | 2.1 mm | 6 | |
| 2 Sept. |  Sunny | 25° /12° | 1.8 mm | 6 | |
| 3 Sept. |  Overcast | 26° /13° | 1.9 mm | 6 | |
| 4 Sept. |  Light rain shower | 25° /13° | 5.9 mm | 6 | |
| 5 Sept. | Patchy rain possible | 25° /12° | 1.7 mm | 6 | |
| 6 Sept. | Sunny | 26° /12° | 0.8 mm | 6 | |
| 7 Sept. | Sunny | 28° /13° | 0.9 mm | 7 | |
| 8 Sept. | Sunny | 25° /14° | 2.7 mm | 6 | |
| 9 Sept. | Patchy rain possible | 23° /13° | 7.6 mm | 5 | |
| 10 Sept. |  Heavy rain at times | 23° /12° | 2.4 mm | 5 | |
| 11 Sept. | Patchy rain possible | 22° /12° | 3.7 mm | 5 | |
| 12 Sept. | Sunny | 23° /11° | 0.8 mm | 5 | |
| 13 Sept. | Light rain shower | 22° /11° | 2 mm | 5 | |
| 14 Sept. | Cloudy | 21° /12° | 3.2 mm | 5 | |
| 15 Sept. | Patchy rain possible | 24° /15° | 1.9 mm | 1.1 | |
| 16 Sept. |  Partly cloudy | 17° /10° | 0 mm | 0.8 | |
| 17 Sept. | Partly cloudy | 21° /10° | 0 mm | 0.4 | |
| 18 Sept. | Sunny | 24° /12° | 0 mm | 1.4 | |
| 19 Sept. | Sunny | 26° /13° | 0 mm | 5 | |
| 20 Sept. | Sunny | 28° /14° | 0 mm | 6 | |
| 21 Sept. | Partly cloudy | 25° /17° | 0 mm | 5 | |
| 22 Sept. | Patchy rain possible | 22° /16° | 4.7 mm | 4 | |
| 23 Sept. | Patchy rain possible | 18° /14° | 2 mm | 4 | |
| 24 Sept. |  Mist | 20° /13° | 0 mm | 4 | |
| 25 Sept. | Patchy rain possible | 21° /14° | 0.4 mm | 4 | |
| 26 Sept. | Patchy rain possible | 18° /11° | 4 mm | 3 | |
| 27 Sept. | Overcast | 19° /10° | 0 mm | 3 | |
| 28 Sept. | Patchy rain possible | 18° /13° | 1.7 mm | 3 | |
| 29 Sept. |  Moderate rain at times | 18° /8° | 3.2 mm | 5 | |
| 30 Sept. | Overcast | 18° /7° | 0.3 mm | 4 | |
| Next | |||||
Guide for Basel in September
In September, Basel, Switzerland experiences a transition from the lingering warmth of summer to the crisp coolness of autumn. At the beginning of the month, the weather in Basel is typically pleasant, with average temperatures around 18° and occasional sunny days.
However, as the month progresses, the temperatures gradually begin to drop. By the end of September, the city experiences cooler weather, with average temperatures around 14°.
The beginning of September in Basel often sees mild and comfortable conditions, making it an ideal time to explore the city's outdoor attractions and enjoy al fresco dining along the Rhine River. As the month progresses, the weather becomes cooler, and occasional rain showers become more frequent.
Visitors to Basel towards the end of September should be prepared for cooler temperatures and the possibility of rain, making it advisable to pack layers and a waterproof jacket.
Overall, September in Basel offers a mix of late summer warmth and early autumn coolness, providing a diverse experience for travelers.
Whether enjoying the last days of outdoor activities or embracing the onset of fall, visitors to Basel can appreciate the changing weather and the unique atmosphere it brings to the city.
Basel in September - FAQ
September rainfall patterns in Basel
UV exposure in Basel during September
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