Siena features a transitional Mediterranean climate with hot, sunny summers and relatively mild, damp winters. The city experiences four distinct seasons, moderate rainfall spread throughout the year, and abundant sunshine in summer. Spring and autumn are especially pleasant, offering mild temperatures and vibrant landscapes, making Siena a captivating destination year-round.
The best times to travel section shows how the months compare for a visit, so you can find the time of year that fits what you want to do.
Background colours of the months:
The colour shows the typical temperature: yellow (hot), green (mild) and blue (cold). How strong the colour is shows the travel season: full colour means high season, soft colour means shoulder season and soft-striped means off season.
Weather symbols:
Each month has one symbol showing what the weather is typically like, such as hot and sunny, freezing or a rainy or snowy season. Use them to quickly spot months that match the weather you want, or to avoid the ones that don't.
Crowdedness:
The people icon shows how busy the place usually is. The more people, the more crowded it gets.
Additional notes:
The grey info boxes point out special things worth knowing, like recurring weather issues or seasonal events.
Siena’s climate is shaped by its inland Tuscan location and moderate elevation. Summers (June–August) are hot and sunny, with average highs of 28–32°C and lows of 16–19°C. Rainfall is rare in summer, with July being the driest month, and humidity is usually low, making the heat more comfortable. Nights tend to cool off, providing relief from daytime warmth. Occasional heatwaves can push temperatures above 35°C, but thunderstorms from the Apennines may break the heat. Sunshine is abundant, with up to 10–11 hours per day in July and August.
Winters (December–February) are relatively mild but can be chilly, with average highs of 8–11°C and lows around 2–4°C. Snow is rare, though occasional snowfalls can occur, especially during cold spells. Rain is more frequent in winter, with November and December being the wettest months. Fog and mist often settle over the hills, creating atmospheric scenes. Spring (March–May) and autumn (September–November) are transitional and particularly pleasant, with highs from 14°C in March to 24°C in May, and from 25°C in September to 15°C in November. These seasons bring blooming landscapes, harvest festivals, and moderate rainfall. Annual precipitation averages 825–900 mm, and Siena enjoys around 2,350–2,400 hours of sunshine per year. Winds are generally light to moderate, with breezier days in late winter and early spring.
| Average climate data for Siena, Italy | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
| Average maximum temperature (°C) | 8 | 10 | 13 | 17 | 20 | 25 | 30 | 30 | 24 | 19 | 14 | 10 | 30 |
| Average minimum temperature (°C) | 2 | 2 | 4 | 7 | 9 | 13 | 15 | 16 | 13 | 10 | 7 | 3 | 2 |
| Average precipitation (mm) | 31 | 28 | 27 | 29 | 39 | 27 | 17 | 14 | 35 | 32 | 49 | 34 | 361 |
| Average rainfall days (days) | 11 | 11 | 12 | 12 | 14 | 9 | 6 | 6 | 9 | 10 | 12 | 11 | 124 |
| Average snowfall (mm) | 13 | 20 | 10 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 5 | 48 |
| Average snowfall days (days) | 1 | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 4 |
| Average relative humidity (%) | 84 | 80 | 77 | 77 | 77 | 74 | 64 | 63 | 72 | 79 | 85 | 81 | 76 |
| Average wind speed (km/h) | 9 | 11 | 11 | 9 | 8 | 7 | 7 | 7 | 8 | 8 | 9 | 8 | 9 |
| Average daily daylight hours (h) | 9 | 10 | 11 | 13 | 14 | 15 | 15 | 13 | 12 | 11 | 9 | 9 | 12 |
| Average daily sunshine hours (h) | 5 | 5 | 7 | 9 | 10 | 11 | 11 | 11 | 10 | 6 | 5 | 5 | 8 |
| Average cloud coverage (%) | 45 | 44 | 38 | 35 | 32 | 21 | 15 | 12 | 24 | 34 | 44 | 41 | 32 |
| Average UV index | 2 | 3 | 4 | 4 | 5 | 6 | 6 | 6 | 5 | 4 | 3 | 2 | 4 |
The best time to visit Siena is in spring (mid-April to mid-June) and autumn (September to early October), when temperatures are mild (16–25°C), rainfall is moderate, and the city is lively with festivals and outdoor events. These seasons offer ideal conditions for sightseeing, enjoying local cuisine, and exploring the Tuscan countryside, with fewer crowds than summer.
The least favourable time to visit is from late November to February, when Siena is coldest, daylight hours are shortest, and rain, fog, and occasional snow are more frequent. While winter brings festive charm and quieter streets, outdoor activities can be limited by chilly, damp, and unpredictable weather.
Siena has a transitional Mediterranean climate with hot, sunny summers and mild, damp winters. Spring and autumn are mild and pleasant, with moderate rainfall and vibrant landscapes. Rain falls throughout the year, but summer is drier.
Summer temperatures in Siena typically reach 28–32°C, with occasional peaks above 35°C during heatwaves. Nights are cooler, and humidity is usually low, making the heat more comfortable.
Snow is rare in Siena, but occasional snowfalls can occur in winter, especially during cold spells. When it does snow, it usually melts quickly and rarely disrupts city life.
Rain falls year-round, but November and December are usually the wettest months. Spring and autumn also see moderate rainfall, while summer is generally dry with only a few rainy days.
Siena enjoys around 2,350–2,400 hours of sunshine annually. July and August are the sunniest months, with up to 10–11 hours of sunshine per day, while winter averages 3–5 hours daily.
Bring warm, waterproof layers for winter. In spring and autumn, pack layers and a light rain jacket. For summer, light, breathable clothes, sun protection, and a hat are essential for hot, sunny days.
Siena is not particularly windy, but breezes are more common in late winter and early spring. Humidity is moderate year-round, lowest in summer and highest in autumn and winter.
The warmest month, with the highest average maximum temperature, is August (30.3 °C). The month with the lowest average maximum temperature is January (8.4 °C). Overall, the average maximum temperature over the whole year is 18.4 °C.
The month with the highest average minimum temperature is August (16.4 °C). The coldest month, with the lowest average minimum temperature, is January (1.9 °C). Overall, the average minimum temperature over the whole year is 8.5 °C.
The wettest month, with the highest amount of precipitation, is November (49.3 mm). The driest month, with the least amount of precipitation, is August (14 mm). Over the whole year there are 361.5 mm of rainfall on average.
The month with the most days of rain is May (13.5 days). The month with the fewest days of rain is August (5.9 days). Over the whole year there are 123.8 days of rain on average.
The month with the most snowfall is February (19.8 mm). The months with the least snowfall are April, May, June, July, August, September, October and November (0 mm). Over the whole year there are 47.8 mm of snowfall on average.
The month with the most days of snowfall is February (1.5 days). The months with the fewest days of snowfall are April, July, September and October (0 days). Over the whole year there are 3.6 days of snowfall on average.
The month with the highest average relative humidity is November (85.3 %). The month with the lowest average relative humidity is August (63.3 %). The overall average relative humidity over the whole year is 76.1 %.
The windiest month, with the highest average wind speed, is February (10.9 km/h). The calmest month, with the lowest average wind speed, is June (7.1 km/h). The overall average wind speed over the whole year is 8.6 km/h.
The month with the cloudiest skies, so the highest cloud coverage, is January (44.7 %). The month with the clearest skies, so the lowest cloud coverage, is August (12.4 %). Over the whole year there is an average cloud coverage of 32 %.
The month with the longest days, so the most daylight, is June (Average daylight: 15 h). The month with the shortest days, so the least daylight, is December (Average daylight: 9 h). Over the whole year there are 11.8 h of daylight per day on average.
The month with the most sunshine per day is July (Average sunshine: 11.1 h). The month with the least sunshine per day is January (Average sunshine: 5.1 h). Over the whole year there are 8 h of sunlight per day on average.
The months with the highest average UV index are June, July and August (UV index: 6). The months with the lowest average UV index are January and December (UV index: 2). Over the whole year the average UV index is 4.2.
