The month in detail
What to expect in September
Autumn in Siena is often underrated: 26°C, golden light and declining crowds. An interesting window. Rain risk remains low (22% of days), leaving good room for outdoor activities. A good balance between weather and crowds, even if June (8.7/10) remains theoretically better.
September ranks 2 out of 12 months in Siena. Compared to August: −6°C daytime, 9 pts more rainy days, −1.2h of sun per day.
This month's conditions
What it's like in September
UV index
5 · moderate
protect during midday hours
Feels like
comfortable
13°
Daylight
12.3h of daylight
Air quality
good
AQI 27
Compare
Is September the right month?
The best month in Siena is June (8.7/10), 0.2 pt higher than September.
Book
Plan your trip
Hotels at their lowest outside peak season, highest on comfortable months. Shoulder seasons offer a good price/climate compromise.
Stay
Hotels & rentals · Siena
Expedia →
Activities
Tours, tickets, experiences
See ↓
Flights
Multi-airline comparator
Kiwi →
🎟️ Activities & tours · Siena
GetYourGuide selection · free cancellation
Practical info
What you need to know before you go
Three angles: the country (language, currency, safety, budget), the year-round climate, and the specifics of a beach holiday.
Country · Italy
🗣️LanguageItalian
💶CurrencyEuro (€)
🚗DrivingRight-hand
🛡️Safety ⓘVery safe · 1/5
💰Cost of living ⓘModerate · 3/5
🌡️ Climate
🌍Climate typeTemperate oceanic
📈Climate trend ⓘStable
🔥Hottest monthJuly · 32°C
❄️Coolest monthJanuary · 10°C
🌧️Rainiest month ⓘNovember · 33%
🏖️ Beach holiday
📅Peak seasonJuin → Sept
🏖️Swell (Sept–Mar) ⓘModérée
🛂VisaSchengen · 90 days
Explore
Other destinations in September
If September doesn't convince you for this destination, compare with others.
Location
Where is Siena ?
Global position + regional geographic context.
🌍 World
🔍 Geographic context
ItalyTemperate oceanic climate with a 8.7 → 4.1 gap between best and worst month. 10 years of ERA5 data to choose by project.
43.32°N · 11.33°E
Questions
Frequently asked questions
What is the best time to visit Siena?
June is the best month with 29.0°C highs, 16.0°C lows, 9.1h of sunshine and 20.0% rainy days. The months of June & July offer comparable conditions.
How many hours of sunshine does Siena get in June?
Siena averages 9.1 sunshine hours per day in June. It is the sunniest month with a climate score of 8.4/10.
What is the rainiest month in Siena?
January is the most unfavourable month with January has the lowest climate score of the year and the lowest climate score of the year.
What are the temperatures at night in Siena in June?
In June, overnight lows reach 16.0°C, while afternoon highs average 29.0°C.
Is Siena good in winter?
In winter (December-February), Siena scores 4.0/10 on average — Difficult period — prefer the peak season.. The best month overall remains June with a score of 8.4/10.
When should you avoid Siena?
January is the most difficult month to visit Siena, with January has the lowest climate score of the year. Climate conditions are at their lowest of the year during this period.
Do you need sun protection in Siena in September?
The average UV index reaches 5 in September in Siena (moderate), with about 12.3h of daylight. Protect during midday hours.