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Siena Weather and Climate: A Comprehensive Guide

Siena has a warm maritime climate that is strongly influenced by the Mediterranean sea. Due to this influence the weather is very stable. This means summer and winter temperatures are not very far apart and it rarely gets really hot or extremely cold. Rainfall is evenly distributed throughout the year, but in summer months the average rainfall is a bit lower. In winter months, the average daily temperature is around 10°C .

Average maximum day and minimum night temperature

Depending on the time of the year, temperatures range from very warm to chilly in Siena. Typically, average maximum daytime temperatures range from a very warm 31°C in August to a chilly 10°C in the coolest month, January.

Nights are cooler, with lows often dropping to around 2°C during the colder months. Check out our detailed temperature page for more information.

Temperature ranges by month

Precipitation and rainy days

Generally, Siena has a moderate amount of precipitation, averaging 903 mm of rain/snowfall annually. The climate in Siena shows significant variation throughout the year. Expect high rainfall in November, with an average of 121 mm of precipitation over 14 rainy days.

In contrast, July offers drier and sunnier days, with around 33 mm of rainfall over 6 rainy days. For more details, please visit our Siena Precipitation page.

The mean monthly precipitation over the year, including rain, hail and snow

Sunshine over the year

For those who appreciate different seasons, Siena serves as an ideal destination. Expect longer, more sun-filled days in July with an average of 11.7 hours of sunshine daily, and embrace the darker days in November, offering only 3.3 hours of daily sunlight. Visit our detailed sunshine hours page for more information.

Monthly hours of sunshine

Daily hours of sunshine

Forecast for Siena

Sat   Dec 21
10°C | 0°C
E 1 m/s
almost clear and no rain

almost clear and no rain

Sun   Dec 22
10°C | -2°C
SW 5 m/s
7.2 mm
broken clouds and rain

broken clouds and rain

Mon   Dec 23
9°C | 1°C
NW 3 m/s
0.7 mm
partly cloudy and small chance of slight sleet

partly cloudy and small chance of slight sleet

The best time of year to visit Siena in Italy

During the months of May, September and October you are most likely to experience good weather with pleasant average temperatures that fall between 20°C and 26°C.

Other facts from our historical weather data:
  • When is summer in Siena?
    The hottest season / summer takes place in June, July, August and September.
  • Which is the warmest month in Siena?
    August has an average maximum temperature of 31°C and is the warmest month of the year.
  • Which is the coldest month in Siena?
    The coldest month is January with an average maximum temperature of 10°C.
  • Which is the wettest month in Siena?
    November tops the wettest month list with 121 mm of rainfall.
  • Which is the driest month in Siena?
    July is the driest month with 33 mm of precipitation.
  • Which is the sunniest month in Siena?
    July is the sunniest month with an average of 350 hours of sunshine.

  • No idea where to travel to this year? We have a tool that recommends destinations based on your ideal conditions. Find out where to go with our weather planner.