September 12 is generally a great time to visit Siena. While there is a slight chance of rain (21%), showers are usually brief. Expect comfortable 26°C weather. Expect a bustling atmosphere in Siena right now—this is when the city truly comes alive with visitors.
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Essential Travel Info for Siena
Currency
EUR
€ Euro
Language
Italian
+1 more
Driving
Right side
Safety
High Safety
GPI: 1.643
Siena Weather Forecast for September 12
"Warm & Sunny. Expect average highs of 26°C. 21% chance of rain."
What to Wear in Siena in September
Based on historical data for September 12, Siena typically experiences temperatures between 14.7°C and 26°C. We recommend packing t-shirt, light clothing to stay comfortable. Trends suggest it will stay mostly dry (21% rain probability), but checking the forecast before heading out is always wise.
Complete Packing Guide
Weekly breakdown & essential items for Siena
Smart Suitcase
- T-Shirt
- Light Clothing
Average High
26°C
Daytime Peak
Average Low
14.7°C
Nighttime Low
Feels Like
26.8°C
☀️ Feels accurate
Rain Chance
21%
Avg 1.5mm if it rains
Cloud Cover
39%
Overcast
Pressure
1015 hPa
Medium volatility
Siena Weather Conditions & UV Index
Weather Confidence
30-year variance analysis
Based on 10 years of data
🎯 This date historically delivers consistent weather 91% of the time. Safe to plan outdoor activities with confidence.
Sun Exposure
UV Index & Safety Guide
Protection Needed
SPF 30 recommended
05:00 - 10:00
16:00 - 18:00
Type I-II
🔴 24 min to burn
Type III-IV
🟡 36 min to burn
Type V-VI
🟢 60 min to burn
UV estimate based on latitude, season & cloud cover. Actual UV may vary.
Outdoor Comfort
How pleasant is it outside?
Dew Point
19.4°C
Noticeable
Heat Stress
Low
No heat warning
😊 Best outdoor time:
Any time during daylight hours
Travel & Logistics Insights
Local Calendar
Business Day
Standard hours in Italy
Flight Traffic
High
95/100 pressure index
Health Advisory
Required
1 vaccine • View Details →
Landing Slots
~61
Daily arrival options (inc. codeshare)
Sunrise, Sunset & Wind in Siena
Daylight & Sun
Solar Elevation Cycle
🌅 Sunrise
05:51
☀️ Noon
12:12
🌇 Sunset
18:33
⏱️ Daylight
12h 41m
Wind Speed
12.7 km/h
Gentle breeze
Sunshine
10.4 hrs
Direct Sun (Cloud-free)
Humidity
67%
Slightly humid
Travel Intelligence
Exclusive flight analytics & health data for Siena
Smart Flight Estimator
Airport-to-Airport Logistics
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Add your home location in settings to see airport details.
Travel Health & Safety in Siena
Travel Comfort Index
Real-time tourism conditions
Weather Quality
☀️ Excellent
Tourist Crowds
🟡 Busy
Price Level
💰💰💰 Expensive
Health & Wellbeing
Meteo-Health Forecast
Moderate fluctuations. Some sensitivity possible.
Weather unlikely to affect joint pain.
Moderate fish activity expected.
Air quality is acceptable. Sensitive individuals should limit prolonged outdoor exertion.
Regional Safety Profile
Seismic Activity
Moderate seismic activity. Occasional tremors possible.
"According to 30YearWeather's analysis of 30 years of NASA satellite data, Siena on September 12 averages 26°C with a 21% precipitation probability. Wedding/Outdoor Event Score: 98/100."
— Source: 30YearWeather.com|Data: NASA POWER (1991-2021)|View Methodology
Siena Weather History (2010–2024)
Temperature History
Hall of Fame
Records from last 10 years
Better Alternatives Nearby
Consider these dates within ±7 days
September 5
26.7°C • 18% rain
Score
99
September 7
26.6°C • 18% rain
Score
99
September 9
26.5°C • 18% rain
Score
99
💡 Moving your event by a few days could significantly improve weather conditions
Compare Other Cities
Same date (September 12) in other destinations
🌍 Explore the same date in different destinations around the world
📍 Is Siena Worth Visiting on September 12?
Planning a trip to Siena on September 12? Our historical weather analysis based on 30 years of NASA satellite data shows that this time of year typically offers vibrant summer conditions averaging 26°C with a 21% historical precipitation risk.
✈️ Travel Logistics: Approximately 61 landing slots available daily during this period, indicating manageable crowd levels.
💉 Health Advisory: 7 vaccinations are recommended for Italy, including COVID-19.
📊 Historical Extremes: The hottest September 12 recorded in the last 30 years saw temperatures hit 32.6°C in 2020, while the coldest dropped to 13.4°C in 2019.