Siena weather in September 2025

The temperatures in Siena in September are comfortable with low of 14°C and and high up to 26°C.

You can expect about 3 to 8 days of rain in Siena during the month of September. It’s a good idea to bring along your umbrella so that you don’t get caught in poor weather.

Our weather forecast can give you a great sense of what weather to expect in Siena in September 2025.

If you’re planning to visit Siena in the near future, we highly recommend that you review the 14 day weather forecast for Siena before you arrive.

Temperatures

26° / 14°

Rainy Days

Snowy Days

Dry Days

Rainfall

Sun Hours

11.6

Hrs

Sun	Mon	Tue	Wed	Thu	Fri	Sat
	1 30° /16°	2 29° /16°	3 29° /16°	4 29° /16°	5 29° /16°	6 29° /16°
7 30° /15°	8 29° /16°	9 29° /15°	10 30° /15°	11 29° /15°	12 30° /15°	13 28° /14°
14 29° /15°	15 29° /15°	16 28° /16°	17 27° /15°	18 26° /14°	19 25° /14°	20 25° /13°
21 24° /13°	22 24° /13°	23 24° /12°	24 24° /13°	25 22° /13°	26 24° /13°	27 23° /13°
28 23° /13°	29 23° /12°	30 23° /12°

Explore the weather in Siena in other months

Siena annual weather

Month	Temperatures	Rainy Days	Dry Days	Snowy Days	Rainfall	Weather	More details
January	9° / 2°	5	25	1	74 mm	Ok	Siena in January
February	10° / 2°	5	21	2	85 mm	Bad	Siena in February
March	14° / 4°	5	25	1	73 mm	Good	Siena in March
April	18° / 7°	5	25	0	64 mm	Good	Siena in April
May	21° / 9°	6	25	0	91 mm	Good	Siena in May
June	27° / 14°	6	24	0	70 mm	Perfect	Siena in June
July	30° / 16°	3	28	0	42 mm	Good	Siena in July
August	31° / 17°	3	28	0	38 mm	Good	Siena in August
September	26° / 14°	4	26	0	81 mm	Perfect	Siena in September
October	20° / 10°	4	27	0	79 mm	Good	Siena in October
November	14° / 7°	6	24	0	105 mm	Good	Siena in November
December	10° / 3°	5	25	1	74 mm	Ok	Siena in December