Early autumn · Weather & things to do
Siena in September
Siena cools off: highs slip to 78°F (25°C), from 88°F in August, with lows of 56°F (13°C) and about 2.6 in (66 mm) of rain.
September opens the best stretch on our comfort score, at 90/100 (2nd of 12).
- Avg high
- 78°F (25°C)
- Avg low
- 56°F (13°C)
- Rain
- 2.6 in (66 mm)
- Humidity
- 66%
- Cloud cover
- 50%
- Daylight
- ~12 h 17 min
- Comfort score
- 90/100 · Great
What September feels like
Days are warm, averaging 78°F (25°C), easy weather for being outside from morning to evening.
Mornings start much cooler: lows average 56°F (13°C), about 12°C (22°F) below the afternoon high.
Some rain is likely, about 2.6 in (66 mm) in the month, so pack for a shower or two.
Plan around September
September is one of Siena's best months on the climate data.
- Last warm month for a while: October highs fall to 68°F.
- Opens the best-scoring stretch on our comfort score: April – June and September & October.
- Comfort improves from 81/100 in August to 90/100.
- September sits inside the Apr – Jun, Sep – Oct window our Tuscany Hill Towns route recommends.
What to pack for September
- Light, breathable clothes78°F afternoons
- A warm layer for eveningsnights drop to 56°F
- Packable rain jacket or umbrellaa shower or two is likely
- Comfortable walking shoesmost places below are best reached on foot or with short walks
What to do in Siena in September
September is good outdoor weather here, so these picks lean toward the open air.
Piazza del Campo
Shell-shaped square where the Palio horse race runs in July and August.
Why now September scores 90/100 for comfort, good conditions for being outside.
Pasticceria Nannini
Siena's classic café for espresso, ricciarelli and panforte.
Siena Cathedral
Striped marble cathedral with an inlaid floor and the Piccolomini Library.
Osteria Le Logge
Old pharmacy turned restaurant serving refined Tuscan food.
Torre del Mangia
Tall tower above Palazzo Pubblico with views of Siena's rooftops.
Nearby in September
- Chianti in September~18 mi · highs 79°F, 2.6 in rain · similar daytime temperatures, about as wet
- Val d'Orcia in September~24 mi · highs 76°F, 3.0 in rain · 1°C (2°F) cooler by day, about as wet
- Florence in September~31 mi · highs 79°F, 2.6 in rain · similar daytime temperatures, about as wet
- Piran in September~188 mi · highs 75°F, 4.4 in rain · 2°C (3°F) cooler by day, wetter
NASA POWER 2001–2025 monthly averages on a ~50 km grid. Comfort scores weigh temperature, rain, humidity and cloud: see how we score each month. Check a forecast before you go.
Siena in September: quick answers
Is September a good time to visit Siena?
Yes. On the climate data it's one of the best months, scoring 90/100. Expect highs of 78°F (25°C) and 2.6 in (66 mm) of rain. September is inside the Apr – Jun, Sep – Oct window our Tuscany Hill Towns route recommends.
How hot is Siena in September?
Average highs are 78°F (25°C) and average lows 56°F (13°C), making it the 4th-warmest month by daytime highs.
Does it rain a lot in Siena in September?
Some: about 2.6 in (66 mm) of rain falls across September on average, the 4th-wettest month of the year. The annual total is about 28.6 in (727 mm).
What should I pack for Siena in September?
Bring light, breathable clothes (78°F afternoons), a warm layer for evenings (nights drop to 56°F), packable rain jacket or umbrella (a shower or two is likely) and comfortable walking shoes (most places below are best reached on foot or with short walks).
Routes in season in September
- Tuscany Hill Towns Apr – Jun, Sep – Oct
Planning Siena in September?
Share this September plan with your group, poll everyone on dates and keep the packing list in one place.