Siena
September
Weather in Siena for September 2025
Your guide to Siena weather in September - trends and predictions
In general, the average temperature in Siena at the beginning of September is 30.3 °C. As the month progressed, temperatures tended to significantly cool down, reaching an average of 24.6 °C by the end of September.
Siena sees moderate rainfall in September, averaging 9 rainy days.
Is September a good time to visit Siena? check out the best time to travel to Siena page.
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21
Dry days
9
Rainy days
0
Snow days
29°/15°
Temperatures
15 km/h
Avg max wind
60 %
Avg humidity
Siena in September average weather
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| Mon. | Tue. | Wed. | Thu. | Fri. | Sat. | Sun. |
|---|---|---|---|---|---|---|
| 1  35° | 2  31° | 3  31° | 4 31° | 5  26° | 6 27° | 7 31° |
| 8 28° | 9 30° | 10 30° | 11 30° | 12 28° | 13  22° | 14 25° |
| 15 26° | 16 26° | 17 25° | 18 23° | 19  24° | 20  23° | 21 25° |
| 22 24° | 23 22° | 24 22° | 25 24° | 26 26° | 27 27° | 28 24° |
| 29 24° | 30 25° |
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Temperatures trend during September in Siena
See the weather trend as well as the moving average line
September weather day by day
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| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| 1 Sept. | Sunny | 35° /19° | 0 mm | 9 | |
| 2 Sept. | Thundery outbreaks possible | 31° /17° | 4.5 mm | 7 | |
| 3 Sept. | Patchy rain possible | 31° /17° | 0.9 mm | 7 | |
| 4 Sept. | Patchy rain possible | 31° /17° | 2.3 mm | 7 | |
| 5 Sept. | Patchy light rain with thunder | 26° /17° | 11.2 mm | 6 | |
| 6 Sept. | Patchy rain possible | 27° /17° | 0.1 mm | 6 | |
| 7 Sept. | Patchy rain possible | 31° /15° | 0 mm | 7 | |
| 8 Sept. | Sunny | 28° /16° | 21.1 mm | 7 | |
| 9 Sept. | Sunny | 30° /15° | 18.8 mm | 7 | |
| 10 Sept. | Sunny | 30° /13° | 0 mm | 8 | |
| 11 Sept. | Sunny | 30° /15° | 1.1 mm | 7 | |
| 12 Sept. | Sunny | 28° /14° | 11.8 mm | 7 | |
| 13 Sept. | Partly cloudy | 22° /11° | 3.4 mm | 6 | |
| 14 Sept. | Partly cloudy | 25° /11° | 0 mm | 7 | |
| 15 Sept. | Partly cloudy | 26° /12° | 0 mm | 7 | |
| 16 Sept. | Thundery outbreaks possible | 26° /13° | 0.2 mm | 6 | |
| 17 Sept. | Sunny | 25° /14° | 0.4 mm | 6 | |
| 18 Sept. | Partly cloudy | 23° /14° | 0.2 mm | 6 | |
| 19 Sept. | Mist | 24° /13° | 0.3 mm | 5 | |
| 20 Sept. | Overcast | 23° /13° | 0.5 mm | 5 | |
| 21 Sept. | Patchy rain possible | 25° /13° | 3.1 mm | 6 | |
| 22 Sept. | Light rain shower | 24° /14° | 5.7 mm | 6 | |
| 23 Sept. | Light rain shower | 22° /12° | 5 mm | 5 | |
| 24 Sept. | Patchy rain possible | 22° /12° | 1.4 mm | 5 | |
| 25 Sept. | Partly cloudy | 24° /11° | 3.8 mm | 6 | |
| 26 Sept. | Sunny | 26° /13° | 0 mm | 6 | |
| 27 Sept. | Sunny | 27° /14° | 1 mm | 7 | |
| 28 Sept. | Sunny | 24° /11° | 0.1 mm | 6 | |
| 29 Sept. | Sunny | 24° /10° | 0 mm | 6 | |
| 30 Sept. | Sunny | 25° /10° | 0 mm | 7 | |
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Important Notice
Our weather forecast for Siena in September is based on the analysis of historical data rather than real-time forecast models. While this provides a general overview, weather conditions can change. We recommend that you check the Siena forecast closer to your planned date for the most up-to-date weather information.
Siena in September - FAQ
What are the expected maximum and minimum temperatures in Siena during September?
During September, expect a variety of temperatures with highs around 29° and lows near 15°, suitable for diverse activities and preferences.
How much rainfall should be expected in Siena during September?
In September, Siena can expect light to moderate rainfall, totaling 40.7 mm across approximately 9 days. Occasional showers are possible, and planning ahead for them could be helpful.
What are the typical wind conditions in Siena during September?
The average wind speed in Siena during September is 15 km/h, suggesting breezy to windy conditions, depending on your activities.
What to pack to Siena in September?
As you prepare for your trip to Siena in September, it's important to consider the typical weather patterns for the time of year. Below is a carefully tailored packing list to ensure that your time in Siena, during September, is comfortable and enjoyable, regardless of the weather conditions.
- Clothing
- Lightweight Clothing: T-shirts, blouses, shorts, skirts
- Rain Gear: Lightweight, waterproof clothing
- Footwear
- Waterproof Shoes
- Sandals/Flip-flops: Comfortable for warm climates
- Accessories
- Sunglasses: For sun protection
- Sun Hats: Wide-brimmed hats for sun protection in warm weather
- Umbrellas/Raincoats: For rainy days
- Personal Items
- Sunscreen: High SPF for sunny destinations
- Lip Balm with SPF: To protect against chapped lips
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