September 25 is generally a great time to visit Siena. While there is a slight chance of rain (28%), showers are usually brief. Expect comfortable 22°C weather. As it's peak season for Siena, we recommend booking your stay well in advance to secure the best rates.
View the full calendar
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 25
"Mild & Comfortable. Expect average highs of 22.2°C. 28% chance of rain."
What to Wear in Siena in September
Based on historical data for September 25, Siena typically experiences temperatures between 12.4°C and 22.2°C. We recommend packing light jacket, long pants to stay comfortable. With a 28% chance of rain, keeping a raincoat or umbrella handy is a smart move.
Complete Packing Guide
Weekly breakdown & essential items for Siena
Smart Suitcase
- Light Jacket
- Long Pants
Average High
22.2°C
Daytime Peak
Average Low
12.4°C
Nighttime Low
Feels Like
22.6°C
☀️ Feels accurate
Rain Chance
28%
Avg 2.3mm if it rains
Cloud Cover
47%
Overcast
Pressure
1015.4 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 93% of the time. Safe to plan outdoor activities with confidence.
Sun Exposure
UV Index & Safety Guide
Protection Needed
SPF 30 recommended
06:00 - 10:00
16:00 - 18:00
Type I-II
🔴 27 min to burn
Type III-IV
🟡 41 min to burn
Type V-VI
🟢 68 min to burn
UV estimate based on latitude, season & cloud cover. Actual UV may vary.
Outdoor Comfort
How pleasant is it outside?
Dew Point
17.6°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
06:06
☀️ Noon
12:07
🌇 Sunset
18:09
⏱️ Daylight
12h 3m
Wind Speed
13 km/h
Gentle breeze
Sunshine
9.6 hrs
Direct Sun (Cloud-free)
Humidity
75%
Humid / Damp
Travel Intelligence
Exclusive flight analytics & health data for Siena
Smart Flight Estimator
Airport-to-Airport Logistics
unlock smart flight estimates
Add your home location in settings to see airport details.
Travel Health & Safety in Siena
Travel Comfort Index
Real-time tourism conditions
Weather Quality
⛅ Good
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 25 averages 22.2°C with a 28% precipitation probability. Wedding/Outdoor Event Score: 96/100."
— 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 29
22°C • 16% rain
Score
100
September 28
22°C • 17% rain
Score
99
September 30
21.8°C • 20% rain
Score
99
💡 Moving your event by a few days could significantly improve weather conditions
Compare Other Cities
Same date (September 25) in other destinations
🌍 Explore the same date in different destinations around the world
📍 Is Siena Worth Visiting on September 25?
Planning a trip to Siena on September 25? Our historical weather analysis based on 30 years of NASA satellite data shows that this time of year is characterized by pleasant mild weather averaging 22.2°C with a 28% 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 25 recorded in the last 30 years saw temperatures hit 27.8°C in 2021, while the coldest dropped to 10.6°C in 2016.