December weather forecast
Brentwood, CA

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Scenic and organized home community in Brentwood City, California
Scenic and organized home community in Brentwood City, California

Weather in December

The first month of the winter, December, is still a cool month in Brentwood, California, with temperature in the range of an average low of 41.7°F (5.4°C) and an average high of 55°F (12.8°C).

Temperature

With its high average temperature of 55°F (12.8°C) and a low of 41.7°F (5.4°C), December is regarded as the coldest month.

Humidity

The average relative humidity in December is 71%.

Rainfall

In Brentwood, in December, it is raining for 9.3 days, with typically 1.57" (40mm) of accumulated precipitation. In Brentwood, during the entire year, the rain falls for 62 days and collects up to 10.16" (258mm) of precipitation.

Snowfall

December is the only month when snow falls in Brentwood. The month with the most snowfall days is December, when snow falls for 0.1 days.

Daylight

With an average of 9h and 36min of daylight, December has the shortest days of the year.
On the first day of December in Brentwood, sunrise is at 7:04 am and sunset at 4:47 pm. On the last day of the month, sunrise is at 7:22 am and sunset at 4:57 pm PST.

Sunshine

With an average of 5.8h of sunshine, December has the least sunshine of the year in Brentwood.

UV index

The months with the lowest UV index are January, February, November and December, with an average maximum UV index of 3. A UV Index reading of 3 to 5 represents a medium vulnerability from exposure to the Sun's UV radiation for the average person.
Note: The maximum daily UV index of 3 in December converts into the following recommendations:
Prioritize safety - The need to safeguard skin and eyes from harm is emphasized. Being in direct Sun during midday can be harmful due to intense solar radiation; take precautions. Wearing a wide-brim hat can block approximately 50% of UV radiation, protecting the eyes. Remember this! The UV radiation of the Sun can be nearly doubled by the reflective properties of snow.
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Frequently asked questions

What is the coldest time of year in Brentwood?

Brentwood's coldest month, December, registers temperatures that range from a high of 55°F (12.8°C) to a low of 41.7°F (5.4°C).

What is the usual temperature for Brentwood in December?

The average high-temperature and low-temperature in Brentwood, California, during December are 55°F (12.8°C) and 41.7°F (5.4°C) respectively. The average heat index (a.k.a. 'apparent temperature', 'felt air temperature'), which combines air temperature and relative humidity, in September is evaluated at 87.8°F (31°C).

What is the average humidity in December in Brentwood?

In Brentwood, the average relative humidity in December is 71%.

How much does it rain in Brentwood in December?

In Brentwood, during December, the rain falls for 9.3 days and regularly aggregates up to 1.57" (40mm) of precipitation.

What is the snowiest month in Brentwood?

December has the most snowfall days of the year in Brentwood, California. Snow falls for 0.1 days.

When does it start to snow in Brentwood?

December is the first month it typically snows. Throughout December, there are 0.1 snowfall days.

What is the month with the shortest days in Brentwood?

With an average of 9h and 36min of daylight, December has the shortest days of the year in Brentwood, California.

How many hours of daylight does Brentwood have in December?

In Brentwood, California, the average day length in December is 9h and 35min.

When is the sunrise / sunset in December in Brentwood?

On the first day of December in Brentwood, California, sunrise is at 7:04 am and sunset at 4:47 pm. On the last day of the month, sunrise is at 7:22 am and sunset at 4:57 pm PST.

What is the month with the least sunshine in Brentwood?

December has the least sunshine of the year, with an average of 5.8h of sunshine.

How long on average sun shines in December in Brentwood?

In Brentwood, California, the average sunshine duration in December is 5.8h.

When is the lowest UV index in Brentwood?

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

What is the UV index reading in December in Brentwood?

The average daily maximum UV index in December in Brentwood, California, is 3. A UV Index estimate of 3 to 5 represents a moderate vulnerability from unprotected exposure to UV radiation.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in December
Brentwood, CA

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

The warmest month (with the highest average high temperature) is July (88.5°F).
The month with the lowest average high temperature is December (55°F).

  • Average low temperature in December: 41.7°F

The month with the highest average low temperature is September (57.7°F).
The coldest month (with the lowest average low temperature) is January (41.5°F).

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Average pressure in December
Brentwood, CA

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

The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).

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Average wind speed in December
Brentwood, CA

Average wind speed in December - Brentwood, CA
  • Average wind speed in December: 5mph

The windiest month (with the highest average wind speed) is June (7.8mph).
The calmest months (with the lowest average wind speed) are January and November (4.5mph).

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Average humidity in December
Brentwood, CA

Average humidity in December - Brentwood, CA
  • Average humidity in December: 71%

The month with the highest relative humidity is January (74%).
The month with the lowest relative humidity is September (52%).

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Average rainfall in December
Brentwood, CA

Average rainfall in December - Brentwood, CA
  • Average rainfall in December: 1.57"

The wettest month (with the highest rainfall) is February (2.09").
The driest months (with the least rainfall) are July and August (0.04").

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Average rainfall days in December
Brentwood, CA

Average rainfall days in December - Brentwood, CA
  • Average rainfall days in December: 9.3 days

The month with the highest number of rainy days is March (12.3 days).
The month with the least rainy days is August (0.8 days).

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Average snowfall days in December
Brentwood, CA

Average snowfall days in December - Brentwood, CA
  • Average snowfall days in December: 0.1 days

The month with the highest number of snowfall days is December (0.1 days).
The months with the least snowfall days are January, February, March, April, May, June, July, August, September, October and November (0 days).

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Average daylight in December /
Average sunshine in December
Brentwood, CA

Average daylight in December / Average sunshine in December - Brentwood, 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 5min

The month with the most sunshine is July (Average sunshine: 12h and 6min).
The month with the least sunshine is December (Average sunshine: 5h and 48min).

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Average sunshine days in December
Brentwood, CA

Average sunshine days in December - Brentwood, CA
  • Average sunshine days in December: 21.1 days

The month with the most sunshine days is August (29.8 days).
The month with the least sunshine days is March (17.7 days).

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Average UV index in December
Brentwood, CA

Average UV index in December - Brentwood, CA
  • Average UV index in December: 3

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

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Average cloud cover in December
Brentwood, CA

Average cloud cover in December - Brentwood, CA
  • Average cloud cover in December: 35

The months with the most cloud cover are March and December (Cloud cover 35).
The month with the least cloud cover is July (Cloud cover 5).

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Average visibility in December
Brentwood, CA

Average visibility in December - Brentwood, 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).

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Brentwood, California, USA

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