September · Switzerland
Best time to visit Basel in September Weather, crowds & prices
Weather in Basel in September
Average temperature 15°C, 115 mm of rain, about 12 days with 6+ hours of sunshine and 79% humidity — based on the five most recent complete years of ERA5 data (2021–2025).
September score
7.0/10
Ranked #5 of 12 months
- Avg temp
- 15°C
- Rainfall
- 115 mm
- Humidity
- 79%
- Days with 6h+ sun
- 12
- Crowd Density
- Moderate Crowds
- Average Expenses
- $$ · Moderate Cost ($$)
September in Basel scores 7.0/10 for sightseeing and cultural travel - an above-average month (#5 of 12). Expect around 15°C, 115 mm of rain, and roughly 12 days with 6+ hours of sunshine this month.
Basel meets France and Germany on the Rhine, with a painted old town, world-class museums and Switzerland's oldest university.
September holds up well in Basel — 5th best month
Temperatures hover around 15°C (59°F) — the kind of month where neither heat nor cold forces the schedule.
115 mm of rain signals a properly wet month, with only about 12 days with 6+ hours of sunshine to count on — build indoor options into the schedule.
That is 7/10 on the same scale — 5th of 12 months, versus 8.5/10 for the best month here.
Pack layers you can shed by midday plus one warm layer for the evening, a proper rain shell rather than an umbrella.
Budget for mid-season pricing, and crowds are moderate.
If your dates are flexible, July is materially better in Basel — 1.5 points higher on the same scale.
Frequently asked
- What is the weather like in Basel in September?
- In September, Basel averages 15°C, 115 mm of rain, and about 12 days with 6+ hours of sunshine. Its climate-comfort score is 7.0/10.
- Is September a good time to visit Basel?
- September earns a 7.0/10 climate-comfort score. Use the year-round chart to weigh the weather against your budget and crowd preferences.
- How much does it rain in Basel in September?
- Expect about 115 mm of rain in September. Average humidity is 79% and there are about 12 days with 6+ hours of sunshine.
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Basel, Switzerland. Live activities and tours from GetYourGuide, matched to this destination.