Siena
September
Weather in Siena for September 2026
Your guide to Siena weather in September - trends and predictions
In general, the average temperature in Siena at the beginning of September is 29.1 °C. As the month progressed, temperatures tended to significantly cool down, reaching an average of 23.6 °C by the end of September.
Siena experiences moderate rainfall in September, with an average of 6 rainy days and a total precipitation of 250.6 mm.
Is September a good time to visit Siena? check out the best time to travel to Siena page.
New! Chat with our AI weatherman - it’s amazing and free.
Temperatures
Rain 🌧️
More
24
Dry days
6
Rainy days
0
Snow days
29°/12°
Temperatures
15 km/h
Avg max wind
67 %
Avg humidity
Siena Weather September
Move between months or click on a day
Temperatures trend during September in Siena
See the weather trend as well as the moving average line
September weather in Siena day by day
Click on a date for more information
| Date | Weather | Temperatures | Rain | UV | More |
|---|---|---|---|---|---|
| 1 Sept. |  Sunny | 32° /16° | 0 mm | 8 | |
| 2 Sept. |  Thundery outbreaks possible | 28° /15° | 4.8 mm | 6 | |
| 3 Sept. |  Patchy rain possible | 28° /15° | 0.4 mm | 7 | |
| 4 Sept. | Patchy rain possible | 30° /15° | 1.1 mm | 7 | |
| 5 Sept. |  Patchy light rain with thunder | 27° /15° | 5.6 mm | 7 | |
| 6 Sept. | Patchy rain possible | 28° /15° | 0.1 mm | 7 | |
| 7 Sept. | Patchy rain possible | 31° /14° | 0 mm | 8 | |
| 8 Sept. | Sunny | 28° /15° | 14.1 mm | 7 | |
| 9 Sept. | Sunny | 28° /15° | 13.8 mm | 7 | |
| 10 Sept. | Sunny | 27° /14° | 16.9 mm | 7 | |
| 11 Sept. | Patchy rain possible | 29° /14° | 0.8 mm | 7 | |
| 12 Sept. | Sunny | 27° /13° | 7.9 mm | 6 | |
| 13 Sept. |  Partly cloudy | 23° /12° | 2.3 mm | 6 | |
| 14 Sept. | Partly cloudy | 25° /12° | 0.2 mm | 6 | |
| 15 Sept. | Partly cloudy | 27° /12° | 0 mm | 7 | |
| 16 Sept. | Patchy rain possible | 26° /14° | 0.1 mm | 6 | |
| 17 Sept. | Sunny | 25° /14° | 0.3 mm | 6 | |
| 18 Sept. | Partly cloudy | 26° /13° | 0.1 mm | 7 | |
| 19 Sept. |  Mist | 26° /14° | 0.2 mm | 6 | |
| 20 Sept. |  Overcast | 26° /14° | 0.3 mm | 6 | |
| 21 Sept. | Patchy rain possible | 26° /14° | 2 mm | 6 | |
| 22 Sept. | Light rain shower | 25° /14° | 5.6 mm | 6 | |
| 23 Sept. | Light rain shower | 23° /13° | 6.3 mm | 5 | |
| 24 Sept. | Patchy rain possible | 21° /11° | 1 mm | 5 | |
| 25 Sept. | Partly cloudy | 23° /11° | 2.9 mm | 5 | |
| 26 Sept. | Patchy rain possible | 25° /12° | 0 mm | 6 | |
| 27 Sept. | Sunny | 25° /13° | 0.7 mm | 6 | |
| 28 Sept. | Sunny | 23° /10° | 0.1 mm | 6 | |
| 29 Sept. | Sunny | 23° /10° | 0 mm | 6 | |
| 30 Sept. | Partly cloudy | 25° /10° | 0 mm | 6 | |
| Next | |||||
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.
Change Month
Siena weather in September vs August vs October
Compare September weather in Siena with the previous and following months. See how temperature, rainfall, wind, and other conditions change throughout the year to help you plan your visit.
| August | September | October | |
|---|---|---|---|
| Weather | Sunny | Sunny | Patchy rain possible |
| Temperatures | 36°/16° | 29°/12° | 24°/9° |
| Rainfall | 154 mm | 251 mm | 267 mm |
| Wind | 17.8 km/h | 14.8 km/h | 14 km/h |
| Humidity | 57% | 67% | 75% |
| Rainy days | 5 days | 6 days | 12 days |
| Dry days | 26 days | 24 days | 19 days |
Planning a trip to Siena? Discover the best time to visit
Siena in September - FAQ
What are the expected maximum and minimum temperatures in Siena during September?
Enjoy moderate daytime temperatures of up to 29° and cooler nights around 12°. Ideal for a range of outdoor activities, from hiking to city tours.
How much rainfall should be expected in Siena during September?
Significant rainfall exceeding 250.6 mm is expected in Siena during September, occurring over more than 6 days. Preparing for wet conditions is recommended in your planning.
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
- Scarves: To protect you from the cold wind
- Gloves/Mittens: Essential for cold weather
- Warm Hats: Warm hats for insulation in cold weather
- Umbrellas/Raincoats: For rainy days
- Personal Items
- Sunscreen: High SPF for sunny destinations
- Lip Balm with SPF: To protect against chapped lips
September rainfall patterns in Siena
Explore the daily rainfall trends and prepare for Sienas September weather 💧
UV exposure in Siena during September
Stay informed about UV levels for safe outdoor activities throughout the month of September ☀️
Quick links
More Siena weather pages
You are here
Where is Siena?Get accurate weather forecasts for Siena, located at latitude 43.318 and longitude 11.331. Stay updated with localized weather information tailored for Siena.
Found a mistake?
We appreciate your attention to details. Tell us here.