December weather forecast
Glen Ellen, CA

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Weather in December

The first month of the winter, December, is still a cool month in Glen Ellen, California, with an average temperature fluctuating between 41.4°F (5.2°C) and 55°F (12.8°C).

Temperature

December, known for its average high temperature of 55°F (12.8°C) and an average low temperature of 41.4°F (5.2°C), is the coldest month.

Humidity

In December, the average relative humidity in Glen Ellen is 73%.

Rainfall

In Glen Ellen, in December, it is raining for 10.6 days, with typically 2.72" (69mm) of accumulated precipitation. In Glen Ellen, during the entire year, the rain falls for 73.3 days and collects up to 15.47" (393mm) of precipitation.

Daylight

The month with the shortest days is December, with an average of 9h and 30min of daylight.
On the first day of December, sunrise is at 7:08 am and sunset at 4:49 pm. On the last day of the month, sunrise is at 7:27 am and sunset at 4:59 pm PST.

Sunshine

December has the least sunshine of the year in Glen Ellen, with an average of 5.6h of sunshine.

UV index

January, February, November and December, with an average maximum UV index of 3, are months with the lowest UV index in Glen Ellen. A UV Index of 3 to 5 symbolizes a medium health hazard from unprotected exposure to Sun's UV rays for ordinary individuals.
Note: In December, a regular UV index of 3 translates into these guidelines:
Exercise caution. The susceptibility of light skin individuals to burns is less than 30 minutes. Midday Sun has the strongest UV rays, making it crucial to limit exposure and find shade. Sun-related eye harm can be minimized with proper sunglasses offering UVA and UVB coverage.

Frequently asked questions

What part of the year is the coldest in Glen Ellen?

December is the coldest month, exhibiting average temperatures of 55°F (12.8°C) at the peak and 41.4°F (5.2°C) at the base.

What are December temperatures in Glen Ellen?

In December, the average high-temperature and low-temperature in Glen Ellen are 55°F (12.8°C) and 41.4°F (5.2°C) respectively. The average heat index (a.k.a. 'apparent temperature', 'real feel'), which factors the actual air temperature with the relative humidity, in September is evaluated at 82.4°F (28°C).

What is the average humidity in December in Glen Ellen?

The average relative humidity in December is 73%.

How many days does it rain in December in Glen Ellen?

In Glen Ellen, in December, it is raining for 10.6 days, with typically 2.72" (69mm) of accumulated precipitation.

What is the month with the shortest days in Glen Ellen?

With an average of 9h and 30min of daylight, December has the shortest days of the year in Glen Ellen, California.

What is the average length of the day in December in Glen Ellen?

The average day length in December is 9h and 33min.

When is the sunrise / sunset in December in Glen Ellen?

In December, on the first day of the month, sunrise is at 7:08 am and sunset at 4:49 pm. On the last day of the month, in Glen Ellen, sunrise is at 7:27 am and sunset at 4:59 pm PST.

What is the month with the least sunshine in Glen Ellen?

With an average of 5.6h of sunshine, December has the least sunshine of the year.

How long on average sun shines in December in Glen Ellen?

In Glen Ellen, California, the average sunshine duration in December is 5.6h.

When is the lowest UV index in Glen Ellen?

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

What is the UV index reading in December in Glen Ellen?

In December, the average daily maximum UV index in Glen Ellen, California, is 3. A UV Index value of 3 to 5 symbolizes a moderate health threat from exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in December
Glen Ellen, CA

Average temperature in December - Glen Ellen, CA
  • Average high temperature in December: 55°F

The warmest month (with the highest average high temperature) is August (82.9°F).
The month with the lowest average high temperature is December (55°F).

  • Average low temperature in December: 41.4°F

The month with the highest average low temperature is August (54.9°F).
The coldest month (with the lowest average low temperature) is December (41.4°F).

Average pressure in December
Glen Ellen, CA

Average pressure in December - Glen Ellen, CA
  • Average pressure in December: 30.11"Hg

The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).

Average wind speed in December
Glen Ellen, CA

Average wind speed in December - Glen Ellen, CA
  • Average wind speed in December: 4.8mph

The windiest month (with the highest average wind speed) is May (6.2mph).
The calmest month (with the lowest average wind speed) is November (4.4mph).

Average humidity in December
Glen Ellen, CA

Average humidity in December - Glen Ellen, CA
  • Average humidity in December: 73%

The month with the highest relative humidity is March (76%).
The month with the lowest relative humidity is September (59%).

Average rainfall in December
Glen Ellen, CA

Average rainfall in December - Glen Ellen, CA
  • Average rainfall in December: 2.72"

The wettest month (with the highest rainfall) is February (3.43").
The driest months (with the least rainfall) are July and August (0.04").

Average rainfall days in December
Glen Ellen, CA

Average rainfall days in December - Glen Ellen, CA
  • Average rainfall days in December: 10.6 days

The month with the highest number of rainy days is March (13.4 days).
The month with the least rainy days is August (0.8 days).

Average daylight in December /
Average sunshine in December
Glen Ellen, CA

Average daylight in December / Average sunshine in December - Glen Ellen, CA
  • Average daylight in December: 9h and 3min

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 30min).

  • Average sunshine in December: 5h and 4min

The month with the most sunshine is July (Average sunshine: 12h and 0min).
The month with the least sunshine is December (Average sunshine: 5h and 36min).

Average sunshine days in December
Glen Ellen, CA

Average sunshine days in December - Glen Ellen, CA
  • Average sunshine days in December: 19.4 days

The month with the most sunshine days is July (28.7 days).
The month with the least sunshine days is March (16.1 days).

Average UV index in December
Glen Ellen, CA

Average UV index in December - Glen Ellen, CA
  • Average UV index in December: 3

The months with the highest UV index are June and July (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 3).

Average cloud cover in December
Glen Ellen, CA

Average cloud cover in December - Glen Ellen, CA
  • Average cloud cover in December: 38

The month with the most cloud cover is March (Cloud cover 40).
The month with the least cloud cover is July (Cloud cover 8).

Average visibility in December
Glen Ellen, CA

Average visibility in December - Glen Ellen, 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).

Glen Ellen, California, USA

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