Siena · AutumnMonth summary
Siena weather in September
✅ Good
🌡️ Temperature min / max
15°C – 26°C
🌧 Rainy days
28% of days
☀️ Sunshine
11.7h per day on average
🌊 🌊 Season
Autumn
⭐ ⭐ Weather score
8.3/10
📅 📅 Best month
June (9.0/10)
Quick decision
Should you visit Siena in September?
✅ Good
✅ Yes if: you want good weather with lower prices than peak season.
❌ No if: you need guaranteed perfect weather — some mixed days are possible.
Our take: Favourable conditions in September (8.3/10). June scores higher but the gap is small.
By trip type
Siena in September by trip type
- 🏙️ 🏙️ City break / culture : ✅ Good
- 🚶 🚶 Outdoor activities : ✅ Good
- 🏖️ Beach / swimming : ✅ Good
- 💰 💰 Budget : 💸 Peak season
Local context
What to expect in September
🎯 Grape harvest — winery visits, tastings and festive atmosphere in the vineyards Autumn in Siena is often underrated: 26°C, golden light and declining crowds. An interesting window. Expect rain on 28% of days — a light raincoat in the bag is recommended. A good balance between weather and crowds, even if June (9.0/10) remains theoretically better.
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All months for Siena
Annual table
Month-by-month comparison
| Month | Min °C | Max °C | Rain % | Precip mm | Sun h/d | Score |
|---|---|---|---|---|---|---|
| 🌫️ January | 2°C | 10°C | 29% | 1.7 | 7.4h | 4.8/10 |
| ⛅ February | 3°C | 13°C | 33% | 2.7 | 8.8h | 5.7/10 |
| ⛅ March | 4°C | 15°C | 30% | 2.4 | 10.8h | 7.0/10 |
| 🌤️ April | 7°C | 19°C | 32% | 2.4 | 12.2h | 7.4/10 |
| 🌤️ May | 11°C | 22°C | 42% | 3.0 | 12.9h | 7.7/10 |
| ☀️ June | 16°C | 29°C | 22% | 1.5 | 14.1h | 9.0/10 |
| ☀️ July | 19°C | 32°C | 17% | 0.8 | 14.3h | 8.5/10 |
| ☀️ August | 19°C | 32°C | 19% | 1.2 | 13.0h | 8.2/10 |
| 🌤️ September | 15°C | 26°C | 28% | 2.8 | 11.7h | 8.3/10 |
| 🌤️ October | 11°C | 21°C | 27% | 3.4 | 9.8h | 7.5/10 |
| ⛅ November | 6°C | 15°C | 39% | 3.8 | 8.0h | 5.6/10 |
| 🌫️ December | 3°C | 11°C | 34% | 2.9 | 7.0h | 4.6/10 |
Ideal
Fair
Challenging climate
◀ Current month · Source Open-Meteo · 10 years
📊 Data source
Data based on 10 years of ERA5 records via Open-Meteo, with ECMWF seasonal adjustment. In September, Siena averages 26°C, 28% rainy days and 11.7h of sunshine per day. Overall weather score: 8.3/10.
See methodology →
Comparison
September vs June (best month)
The best month is June (score 9.0/10). Difference:
- 🌡️ Max temperature : +3°C
- 🌧 Rainy days : -6%
- ☀️ Sunshine : +2.4h/day
FAQ
FAQ — Siena in September
Is September a good time to visit Siena?
September is an excellent time to visit Siena (score 8.3/10). With 26°C, 11.7h of sunshine and 28% rain, conditions are very favourable.
What to do in Siena in September?
With 26°C and 11.7h of sunshine, all outdoor activities are possible: hiking, sightseeing and terraces.
Accommodation
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Activities & tours
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