December weather forecast
Siena, Italy

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Weather in December

December in Siena, Italy, marks the arrival of winter with cold temperatures, rare snowfall, and minimal sunshine. The city decks itself up for the holiday season, adding a unique charm to the chilly weather. With a gradual drop in temperature to a low of 3.1°C (37.6°F), winter coats become indispensable. Although the average snowfall registers at 5mm (0.2") over a mere 0.5 days, the onset of winter becomes apparent. The dwindling daylight hours and a slight increase in wind speed make it a perfect time for indoor activities and embracing the cosy Italian cafe culture.

Temperature

With the onset of December, the average high-temperature subtly recedes from November's refreshing 13.6°C (56.5°F) to a chilly 9.5°C (49.1°F). Siena, during the nights of December, experiences an average temperature drop to a wintry 3.1°C (37.6°F).

Humidity

The average relative humidity in December is 82%.

Rainfall

In Siena, in December, it is raining for 10.8 days, with typically 34mm (1.34") of accumulated precipitation. Throughout the year, there are 123.6 rainfall days, and 363mm (14.29") of precipitation is accumulated.

Snowfall

January through March and December are months with snowfall in Siena. December is the first month it typically snows. Throughout December, in the average 0.5 snowfall days, it receives 5mm (0.2") of snow. In Siena, during the entire year, snow falls for 3.6 days and aggregates up to 48mm (1.89") of snow.

Daylight

With an average of 9h and 0min of daylight, December has the shortest days of the year in Siena.
On the first day of December in Siena, sunrise is at 07:27 and sunset at 16:40. On the last day of the month, sunrise is at 07:46 and sunset at 16:48 CET.

Sunshine

The average sunshine in December in Siena is 5.6h.

UV index

The months with the lowest UV index are January and December, with an average maximum UV index of 2. A UV Index estimate of 2, and below, represents a minimal health vulnerability from unprotected exposure to Sun's UV rays for ordinary individuals.
Note: In December, a daily maximum UV index of 2 leads to the following instructions:
Extended sun exposure is not an issue for the majority. Children, infants, and fair-skinned individuals always need to be protected. The Sun is most powerful around mid-day, so it's a good practice to reduce direct exposure. Consider a wide-brim hat essential for effective sun defense covering your face, neck, and eyes. On your guard! Snow's reflection can almost double the intensity of the Sun's UV radiation.

Frequently asked questions

What are the temperatures in Siena in December?

The average high-temperature and low-temperature in Siena, Italy, during December are 9.5°C (49.1°F) and 3.1°C (37.6°F) respectively. The average heat index (a.k.a. 'real feel', 'apparent temperature'), which combines relative humidity and air temperature, in August is calculated to be 34°C (93.2°F).

What is the average humidity in December in Siena?

In Siena, the average relative humidity in December is 82%.

How much does it rain in Siena in December?

In Siena, during December, the rain falls for 10.8 days and regularly aggregates up to 34mm (1.34") of precipitation.

When does it start to snow in Siena?

December is the first month it typically snows in Siena. Throughout December, in the average 0.5 snowfall days, it receives 5mm (0.2") of snow.

What is the month with the shortest days in Siena?

December has the shortest days of the year, with an average of 9h and 0min of daylight.

How many hours of daylight does Siena have in December?

In Siena, the average day length in December is 9h and 2min.

When is the sunrise / sunset in December in Siena?

In December, on the first day of the month, sunrise is at 07:27 and sunset at 16:40. On the last day of the month, in Siena, sunrise is at 07:46 and sunset at 16:48 CET.

How long on average sun shines in December in Siena?

In December, the average sunshine duration in Siena, Italy, is 5.6h.

When is the lowest UV index in Siena?

The months with the lowest UV index in Siena are January and December, with an average maximum UV index of 2.

How high is the UV index in December in Siena?

The average daily maximum UV index in December is 2. A UV Index of 2, and less, symbolizes a low health threat from exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in December
Siena, Italy

Average temperature in December - Siena, Italy
  • Average high temperature in December: 9.5°C

The warmest month (with the highest average high temperature) is August (30.3°C).
The month with the lowest average high temperature is January (8.5°C).

  • Average low temperature in December: 3.1°C

The month with the highest average low temperature is August (16.3°C).
The coldest month (with the lowest average low temperature) is January (1.9°C).

Average pressure in December
Siena, Italy

Average pressure in December - Siena, Italy
  • Average pressure in December: 1018.4mbar

The month with the highest atmospheric pressure is December (1018.4mbar).
The month with the lowest atmospheric pressure is July (1013.5mbar).

Average wind speed in December
Siena, Italy

Average wind speed in December - Siena, Italy
  • Average wind speed in December: 8.3km/h

The windiest months (with the highest average wind speed) are February and March (10.8km/h).
The calmest month (with the lowest average wind speed) is June (7.1km/h).

Average humidity in December
Siena, Italy

Average humidity in December - Siena, Italy
  • Average humidity in December: 82%

The month with the highest relative humidity is November (85%).
The month with the lowest relative humidity is August (63%).

Average rainfall in December
Siena, Italy

Average rainfall in December - Siena, Italy
  • Average rainfall in December: 34mm

The wettest month (with the highest rainfall) is November (50mm).
The driest month (with the least rainfall) is August (14mm).

Average rainfall days in December
Siena, Italy

Average rainfall days in December - Siena, Italy
  • Average rainfall days in December: 10.8 days

The month with the highest number of rainy days is May (13.5 days).
The month with the least rainy days is August (5.8 days).

Average snowfall in December
Siena, Italy

Average snowfall in December - Siena, Italy
  • Average snowfall in December: 5mm

The month with the highest snowfall is February (20mm).
The months with the least snowfall are April, May, June, July, August, September, October and November (0mm).

Average snowfall days in December
Siena, Italy

Average snowfall days in December - Siena, Italy
  • Average snowfall days in December: 0.5 days

The month with the highest number of snowfall days is February (1.4 days).
The months with the least snowfall days are April, May, June, July, August, September and October (0 days).

Average daylight in December /
Average sunshine in December
Siena, Italy

Average daylight in December / Average sunshine in December - Siena, Italy
  • Average daylight in December: 9h and 0min

The month with the longest days is June (Average daylight: 15h and 18min).
The month with the shortest days is December (Average daylight: 9h and 0min).

  • Average sunshine in December: 5h and 4min

The months with the most sunshine are July and August (Average sunshine: 11h and 54min).
The month with the least sunshine is January (Average sunshine: 5h and 18min).

Average sunshine days in December
Siena, Italy

Average sunshine days in December - Siena, Italy
  • Average sunshine days in December: 16.8 days

The month with the most sunshine days is August (23.9 days).
The month with the least sunshine days is February (14.6 days).

Average UV index in December
Siena, Italy

Average UV index in December - Siena, Italy
  • Average UV index in December: 2

The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January and December (UV index 2).

Average cloud cover in December
Siena, Italy

Average cloud cover in December - Siena, Italy
  • Average cloud cover in December: 41

The months with the most cloud cover are January, February and November (Cloud cover 44).
The month with the least cloud cover is August (Cloud cover 13).

Average visibility in December
Siena, Italy

Average visibility in December - Siena, Italy
  • Average visibility in December: 9km

The months with the highest visibility are February, March, April, May, June, July, August, September and December (9km).
The months with the lowest visibility are January, October and November (8km).

Siena, Italy

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