December weather forecast
San Anselmo, CA

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Weather in December

December marks the year-end with the lowest temperatures in San Anselmo, descending to an average low of 45.3°F (7.4°C). The darkness sets in early, and the city gets limited hours of sunshine. Interestingly, the amount of rainfall spikes to 0.67" (17mm), making it the month with the most precipitation. The return to higher humidity levels of 73% and a 38% cloud cover makes for overcast and rather dreary days. As winter sets in, wind speeds ramp up slightly, ushering in a chilly breeze, marking the arrival of the new year.

Temperature

December stands out as San Anselmo's coldest month, with an average high-temperature of 55.4°F (13°C) and a low-temperature of 45.3°F (7.4°C).

Humidity

In December, the average relative humidity is 73%.

Rainfall

In December, the rain falls for 7.2 days. Throughout December, 0.67" (17mm) of precipitation is accumulated. In San Anselmo, during the entire year, the rain falls for 48 days and collects up to 3.94" (100mm) of precipitation.

Daylight

With an average of 9h and 36min of daylight, December has the shortest days of the year.
On the first day of December, sunrise is at 7:08 am and sunset at 4:51 pm. On the last day of the month, sunrise is at 7:26 am and sunset at 5:01 pm PST.

Sunshine

With an average of 5.5h of sunshine, December has the least sunshine of the year.

UV index

The months with the lowest UV index in San Anselmo are January, February, November and December, with an average maximum UV index of 3. A UV Index estimate of 3 to 5 represents a moderate threat to health from exposure to the Sun's UV radiation for ordinary individuals.
Note: The daily maximum UV index of 3 in December interprets into the following advice:
Safety measures are advised. Light-skinned individuals may experience burns in under half an hour. Avoiding direct sun during mid-day hours can prevent harmful UV radiation exposure. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects.
Updated: Jun 17, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the coldest month?

December, with its average high-temperature of 55.4°F (13°C) and an average low-temperature of 45.3°F (7.4°C), holds the record as the coldest month.

What is the temperature in December?

The high-temperature during December is 55.4°F (13°C) and the low-temperature is 45.3°F (7.4°C).

What is the average humidity in December in San Anselmo?

In December, the average relative humidity is 73%.

How many days does it rain in December?

In December, the rain falls for 7.2 days. Throughout December, 0.67" (17mm) of precipitation is accumulated.

What is the month with the shortest days in San Anselmo?

The month with the shortest days is December, with an average of 9h and 36min of daylight.

What is the average length of the day in December?

In San Anselmo, the average day length in December is 9h and 35min.

When are sunrise and sunset in December?

In December, on the first day of the month, sunrise is at 7:08 am and sunset at 4:51 pm. On the last day of the month, sunrise is at 7:26 am and sunset at 5:01 pm PST.

What is the month with the least sunshine?

The month with the least sunshine is December, with an average of 5.5h of sunshine.

How many hours of sunshine does San Anselmo have in December?

In San Anselmo, the average sunshine duration in December is 5.5h.

What are the months with the lowest UV index?

January, February, November and December, with an average maximum UV index of 3, are months with the lowest UV index.

How high is the UV index in December in San Anselmo?

The average daily maximum UV index in December in San Anselmo is 3. A UV Index of 3 to 5 symbolizes a moderate health threat from exposure to the Sun's UV radiation.
Average humidity
Average rainfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in December
San Anselmo, CA

Average temperature in December - San Anselmo, CA
  • Average high temperature in December: 55.4°F

The warmest month (with the highest average high temperature) is September (72.3°F).
The month with the lowest average high temperature is December (55.4°F).

  • Average low temperature in December: 45.3°F

The month with the highest average low temperature is September (56.1°F).
The coldest month (with the lowest average low temperature) is December (45.3°F).

Average pressure in December
San Anselmo, CA

Average pressure in December - San Anselmo, CA
  • Average pressure in December: 30.1"Hg

The month with the highest atmospheric pressure is January (30.13"Hg).
The months with the lowest atmospheric pressure are June, August and September (29.92"Hg).

Average wind speed in December
San Anselmo, CA

Average wind speed in December - San Anselmo, CA
  • Average wind speed in December: 6.2mph

The windiest month (with the highest average wind speed) is May (7.8mph).
The calmest months (with the lowest average wind speed) are October and November (5.5mph).

Average humidity in December
San Anselmo, CA

Average humidity in December - San Anselmo, CA
  • Average humidity in December: 73%

The month with the highest relative humidity is March (77%).
The month with the lowest relative humidity is October (68%).

Average rainfall in December
San Anselmo, CA

Average rainfall in December - San Anselmo, CA
  • Average rainfall in December: 0.67"

The wettest month (with the highest rainfall) is February (0.87").
The driest months (with the least rainfall) are June, July, August and September (0.04").

Average rainfall days in December
San Anselmo, CA

Average rainfall days in December - San Anselmo, CA
  • Average rainfall days in December: 7.2 days

The month with the highest number of rainy days is March (8.8 days).
The months with the least rainy days are June and August (1.2 days).

Average daylight in December /
Average sunshine in December
San Anselmo, CA

Average daylight in December / Average sunshine in December - San Anselmo, CA
  • Average daylight in December: 9h and 4min

The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 36min).

  • Average sunshine in December: 5h and 3min

The month with the most sunshine is July (Average sunshine: 11h and 12min).
The month with the least sunshine is December (Average sunshine: 5h and 30min).

Average sunshine days in December
San Anselmo, CA

Average sunshine days in December - San Anselmo, CA
  • Average sunshine days in December: 22.1 days

The month with the most sunshine days is June (26.4 days).
The month with the least sunshine days is March (20.7 days).

Average UV index in December
San Anselmo, CA

Average UV index in December - San Anselmo, CA
  • Average UV index in December: 3

The months with the highest UV index are April, June, July, August and September (UV index 5).
The months with the lowest UV index are January, February, November and December (UV index 3).

Average cloud cover in December
San Anselmo, CA

Average cloud cover in December - San Anselmo, CA
  • Average cloud cover in December: 38

The month with the most cloud cover is March (Cloud cover 39).
The month with the least cloud cover is September (Cloud cover 19).

Average visibility in December
San Anselmo, CA

Average visibility in December - San Anselmo, CA
  • Average visibility in December: 6mi

The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).

San Anselmo, California, USA

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