December weather forecast
Alameda, CA

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Weather in December

The first month of the winter, December, is still a mild month in Alameda, California, with an average temperature varying between 45.1°F (7.3°C) and 55.9°F (13.3°C).

Temperature

December, known for its average high temperature of 55.9°F (13.3°C) and an average low temperature of 45.1°F (7.3°C), is the coldest month.

Humidity

The average relative humidity in December is 71%.

Rainfall

In Alameda, in December, it is raining for 10.2 days, with typically 1.02" (26mm) of accumulated precipitation. In Alameda, during the entire year, the rain falls for 67.2 days and collects up to 6.1" (155mm) of precipitation.

Ocean temperature

In Alameda, California, the average seawater temperature in December is 54.5°F (12.5°C).
Note: Caution: 54.5°F (12.5°C) temperatures below 50°F (10°C) during swimming can result in intense cold shock and quickened breathing.

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 7:06 am and sunset at 4:50 pm. On the last day of the month, sunrise is at 7:24 am and sunset at 5:00 pm PST.

Sunshine

With an average of 5.9h of sunshine, December has the least sunshine of the year.

UV index

January, November and December, with an average maximum UV index of 3, are months with the lowest UV index. A UV Index reading of 3 to 5 represents a moderate threat to health from exposure to the Sun's UV rays for ordinary individuals.
Note: In December, a regular UV index of 3 translates into these guidelines:
Take precautions. Light skin individuals may get burned in less than 30 minutes. To prevent harmful UV exposure, minimize direct contact with the Sun around midday. Stay sun-safe with clothing that is both closely woven and worn loosely.
Updated: Jul 23, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the coldest time of year?

December, with average temperatures reaching a high of 55.9°F (13.3°C) and a low of 45.1°F (7.3°C), is the coldest month.

What are December temperatures?

The high-temperature, in December, in Alameda, is 55.9°F (13.3°C), while the low-temperature averages to 45.1°F (7.3°C).

What is the average humidity in December?

In December, the average relative humidity is 71%.

How much does it rain in December?

In Alameda, in December, during 10.2 rainfall days, 1.02" (26mm) of precipitation is typically accumulated.

What is the ocean temperature in December?

In Alameda, in December, the average water temperature is 54.5°F (12.5°C). Swimming in 54.5°F (12.5°C) is considered dangerous. Unprotected immersion in temperatures below 50°F (10°C) causes quickly maximum intensity cold shock with hyperventilation.

What is the month with the shortest days?

December has the shortest days of the year, with an average of 9h and 36min of daylight.

How many hours of daylight does Alameda have in December?

In December, the average day length is 9h and 36min.

When are sunrise and sunset in December in Alameda?

On the first day of December, sunrise is at 7:06 am and sunset at 4:50 pm. On the last day of the month, sunrise is at 7:24 am and sunset at 5:00 pm PST.

What is the month with the least sunshine?

December has the least sunshine of the year in Alameda, with an average of 5.9h of sunshine.

How long on average sun shines in December?

In Alameda, the average sunshine duration in December is 5.9h.

When is the lowest UV index?

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

How high is the UV index in December?

In Alameda, the average daily maximum UV index in December is 3. A UV Index reading of 3 to 5 represents 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
Alameda, CA

Average temperature in December - Alameda, CA
  • Average high temperature in December: 55.9°F

The warmest month (with the highest average high temperature) is September (75.9°F).
The month with the lowest average high temperature is December (55.9°F).

  • Average low temperature in December: 45.1°F

The month with the highest average low temperature is September (56.5°F).
The coldest month (with the lowest average low temperature) is January (45°F).

Average pressure in December
Alameda, CA

Average pressure in December - Alameda, CA
  • Average pressure in December: 30.11"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
Alameda, CA

Average wind speed in December - Alameda, CA
  • Average wind speed in December: 5.8mph

The windiest month (with the highest average wind speed) is May (7.2mph).
The calmest months (with the lowest average wind speed) are October and November (5.2mph).

Average humidity in December
Alameda, CA

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

The month with the highest relative humidity is March (75%).
The month with the lowest relative humidity is October (65%).

Average rainfall in December
Alameda, CA

Average rainfall in December - Alameda, CA
  • Average rainfall in December: 1.02"

The wettest month (with the highest rainfall) is February (1.18").
The driest month (with the least rainfall) is July (0.04").

Average rainfall days in December
Alameda, CA

Average rainfall days in December - Alameda, CA
  • Average rainfall days in December: 10.2 days

The month with the highest number of rainy days is March (11.4 days).
The month with the least rainy days is August (1.3 days).

Average sea temperature in December
Alameda, CA

Average sea temperature in December - Alameda, CA
  • Average sea temperature in December: 54.5°F

The best month for swimming (with the highest average sea temperature) is September (57.3°F).
The coldest months (with the lowest average sea temperature) are April and June (53°F).

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

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

The month with the longest days is June (Average daylight: 14h and 42min).
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 0min).
The month with the least sunshine is December (Average sunshine: 5h and 54min).

Average sunshine days in December
Alameda, CA

Average sunshine days in December - Alameda, CA
  • Average sunshine days in December: 19.4 days

The month with the most sunshine days is July (25.4 days).
The month with the least sunshine days is March (17.3 days).

Average UV index in December
Alameda, CA

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

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

Average cloud cover in December
Alameda, CA

Average cloud cover in December - Alameda, CA
  • Average cloud cover in December: 34

The month with the most cloud cover is March (Cloud cover 35).
The month with the least cloud cover is July (Cloud cover 9).

Average visibility in December
Alameda, CA

Average visibility in December - Alameda, 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).

Alameda, California, USA

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