Siena Weather in September
What's the weather like in Siena (Tuscany) in September 2025?
The climate in Siena during September can be summarized as warm and reasonably dry.
September is in the fall / autumn in Siena and is typically the 4th warmest month of the year. Daytime maximum temperatures average around 25°C (76°F), whilst at night 14°C (57°F) is normal.
| Daytime temperature | 24.5°C 76°F |
|---|---|
| Nightly temperature | 14°C 57.1°F |
| Average temperature | 19.2°C 66.6°F |
| Daily sunshine | 7.6 hrs |
| Avg rainfall | 69 mm 2.7 ins |
| Rainy days | 9 days |
| Sea temperature | 23.1°C 73.5°F |
| Humidity | 71% |
| Windspeed | 8.6kph 5 mph |
On average September is the 4th wettest month of the year in Siena with around 69mm 2.7 inches of rain making it a reasonably dry time to visit. This rainfall is typically spread over 9 days, although this may vary considerably.
On the flip side this corresponds to an average of 7.6 hours of sunshine per day.
September temperatures in Siena
September rainfall
September hourly sunshine
The data used in these monthly averages covers a period of over 100 years right up until last year. As such they are a valid prediction of what to expect for the weather in Siena in September 2025.
Other monthly averages
Best places to visit in September
Siena weather stats
| Hottest month: | July | 28.4°C 83.1°F |
|---|---|---|
| Driest month: | July | 30mm 1.2ins |
| Sunniest month: | July | 10.4hrs |
| Coldest month: | January | 9.1°C 48.4°F |
| Wettest month: | November | 103mm 4.1ins |
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