Brentwood
California, USA
Long-term weather forecast
Long-term weather forecast

December weather forecast and climate
Brentwood, CA

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

Temperature

The coldest month is December, with an average high-temperature of 55°F (12.8°C) and an average low-temperature of 41.7°F (5.4°C).

Humidity

The average relative humidity in Brentwood is 71%.

Rainfall

In December, the rain falls for 9.3 days. Throughout December, 1.57" (40mm) of precipitation is accumulated. 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. December has the most snowfall days of the year in Brentwood. Snow falls for 0.1 days.

Daylight

December has the shortest days of the year, with an average of 9.6h of daylight.

Sunshine

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

UV index

Months with the lowest UV index are January, February, November and December, with an average maximum UV index of 3. A UV Index of 3 to 5 symbolizes a moderate health risk from unprotected exposure to the Sun's UV rays for the ordinary person.
Note: The average daily UV index of 3 in December transform into the following instructions:
Take precautions - Protection against sun damage is advised. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. A wide-brim hat offers excellent sun protection for eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. Tightly woven, loose-fitting clothes provide additional protection from the Sun. Beware! The strength of the UV rays is increased nearly double-fold by the reflection of the snow.

What is the coldest month in Brentwood?

With an average high-temperature of 55°F (12.8°C) and an average low-temperature of 41.7°F (5.4°C), December is the coldest month.

What is the temperature in December in Brentwood?

In December, in Brentwood, the average high-temperature is 55°F (12.8°C), and the average low-temperature is 41.7°F (5.4°C).

What is the average humidity in December in Brentwood?

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

How many days does it rain in December in Brentwood?

In Brentwood, in December, it is raining for 9.3 days, with typically 1.57" (40mm) of accumulated precipitation.

When does it start to snow in Brentwood?

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

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.

What is the month with the shortest days in Brentwood?

December has the shortest days of the year, with an average of 9.6h of daylight.

What is the average length of the day in December in Brentwood?

The average length of the day in December in Brentwood is 9.6h.

What is the month with the least sunshine in Brentwood?

The month with the least sunshine in Brentwood, California, is December, with an average of 5.8h of sunshine.

How long on average sun shines in December in Brentwood?

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

What is the month with the lowest UV index in Brentwood?

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

What is the UV index intensity in December in Brentwood?

The average daily maximum UV index in December is 3. A UV Index reading of 3 to 5 represents a moderate vulnerability from the exposure to the Sun's UV radiation.
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).

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%).

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

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

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 lowest number of rainy days is August (0.8 days).

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).
Months with the lowest number of snowfall days are January, February, March, April, May, June, July, August, September, October and November (0 days).

Average daylight in December / Average sunshine in December - Brentwood, CA
  • Average daylight in December: 9.6h

The month with the longest days is June (Average daylight: 14.8h).
The month with shortest days is December (Average daylight: 9.6h).

  • Average sunshine in December: 5.8h

The month with most sunshine is July (Average sunshine: 12.1h).
The month with least sunshine is December (Average sunshine: 5.8h).

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

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