December weather forecast
San Diego, CA

Coronado Island in San Diego, California, USA,
Coronado Island in San Diego, California, USA,

Weather in December

December, the first month of the winter in San Diego, is still a comfortable month, with temperature in the range of an average low of 52.7°F (11.5°C) and an average high of 63.3°F (17.4°C).

Temperature

In San Diego, California, the average high-temperature in December is practically the same as in November - a comfortable 63.3°F (17.4°C). In December, the average low-temperature is 52.7°F (11.5°C).

Humidity

In San Diego, the average relative humidity in December is 62%.

Rainfall

December is the month with the most rainfall in San Diego, California. Rain falls for 5.8 days and accumulates 1.65" (42mm) of precipitation.

Ocean temperature

In San Diego, the average seawater temperature in December is 60.4°F (15.8°C).
Note: For swimming, a surface water temperature of 60.4°F (15.8°C) is not enjoyable for the majority. It is not considered safe, as controlling breathing becomes progressively more difficult as water temperature decreases below 69.8°F (21°C).

Daylight

The month with the shortest days is December, with an average of 10h and 2min of daylight.
On the first day of the month, sunrise is at 6:33 am and sunset at 4:42 pm. On the last day of December, sunrise is at 6:50 am and sunset at 4:52 pm PST.

Sunshine

December has the least sunshine of the year, with an average of 6.7h of sunshine.

UV index

January through March, November and December, with an average maximum UV index of 4, are months with the lowest UV index. A UV Index estimate of 3 to 5 represents a medium health hazard from unprotected exposure to Sun's UV rays for average individuals.
Note: The daily maximum UV index of 4 in December interpret into the following advice:
Take precautions - Protection against sunburn is recommended. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes.
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FAQ

What is the average humidity in December in San Diego?

The average relative humidity in December in San Diego, California, is 62%.

What is the rainiest month in San Diego?

December is the month with the most rainfall in San Diego. Rain falls for 5.8 days and accumulates 1.65" (42mm) of precipitation.

How many days does it rain in December in San Diego?

In December, the rain falls for 5.8 days. Throughout December, 1.65" (42mm) of precipitation is accumulated.

How cold is the water in December in San Diego?

In San Diego, California, the average seawater temperature in December is 60.4°F (15.8°C). Swimming in 60.4°F (15.8°C) is not enjoyable for the majority. Controlling breathing becomes progressively more difficult as surface water temperature decreases below 69.8°F (21°C).

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

The month with the shortest days is December, with an average of 10h and 2min of daylight.

How many hours of daylight does San Diego have in December?

The average day length in December in San Diego is 10h and 2min.

What time are sunrise and sunset in December in San Diego?

On the first day of December, sunrise is at 6:33 am and sunset at 4:42 pm. On the last day of the month, sunrise is at 6:50 am and sunset at 4:52 pm PST.

What is the month with the least sunshine in San Diego?

With an average of 6.7h of sunshine, December has the least sunshine of the year in San Diego.

How long on average sun shines in December in San Diego?

In December, the average sunshine duration in San Diego is 6.7h.

What is the month with the lowest UV index in San Diego?

The months with the lowest UV index in San Diego, California, are January through March, November and December, with an average maximum UV index of 4.

What is the UV index intensity in December in San Diego?

The average daily maximum UV index in December in San Diego, California, is 4. A UV Index reading of 3 to 5 represents a moderate health threat from unprotected exposure to UV radiation.

Average temperature in December
San Diego, CA

Average temperature in December - San Diego, CA
  • Average high temperature in December: 63.3°F

The warmest month (with the highest average high temperature) is August (77.4°F).
The month with the lowest average high temperature is February (63.1°F).

  • Average low temperature in December: 52.7°F

The month with the highest average low temperature is August (65.7°F).
The coldest month (with the lowest average low temperature) is February (51.8°F).

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Average pressure in December
San Diego, CA

Average pressure in December - San Diego, CA
  • Average pressure in December: 30.06"

The month with the highest atmospheric pressure is January (30.09").
The months with the lowest atmospheric pressure are June and September (29.88").

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Average wind speed in December
San Diego, CA

Average wind speed in December - San Diego, CA
  • Average wind speed in December: 5.5mph

The windiest months (with the highest average wind speed) are April and May (6.3mph).
The calmest month (with the lowest average wind speed) is October (5.2mph).

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Average humidity in December
San Diego, CA

Average humidity in December - San Diego, CA
  • Average humidity in December: 62%

The month with the highest relative humidity is June (73%).
The month with the lowest relative humidity is November (59%).

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Average rainfall in December
San Diego, CA

Average rainfall in December - San Diego, CA
  • Average rainfall in December: 1.65"

The wettest month (with the highest rainfall) is December (1.65").
The driest month (with the least rainfall) is June (0.12").

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Average rainfall days in December
San Diego, CA

Average rainfall days in December - San Diego, CA
  • Average rainfall days in December: 5.8 days

The month with the highest number of rainy days is March (7.6 days).
The month with the least rainy days is June (2.7 days).

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Average sea temperature in December
San Diego, CA

Average sea temperature in December - San Diego, CA
  • Average sea temperature in December: 60.4°F

The best month for swimming (with the highest average sea temperature) is August (67.9°F).
The coldest month (with the lowest average sea temperature) is February (58.7°F).

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

Average daylight in December / Average sunshine in December - San Diego, CA
  • Average daylight in December: 10h and 2min

The month with the longest days is June (Average daylight: 14h and 16min).
The month with the shortest days is December (Average daylight: 10h and 2min).

  • Average sunshine in December: 6.7h

The months with the most sunshine are July and August (Average sunshine: 11.9h).
The month with the least sunshine is December (Average sunshine: 6.7h).

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Average sunshine days in December
San Diego, CA

Average sunshine days in December - San Diego, CA
  • Average sunshine days in December: 23.2 days

The month with the most sunshine days is January (24.3 days).
The month with the least sunshine days is July (20.3 days).

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Average UV index in December
San Diego, CA

Average UV index in December - San Diego, CA
  • Average UV index in December: 4

The months with the highest UV index are July, August and September (UV index 6).
The months with the lowest UV index are January, February, March, November and December (UV index 4).

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Average cloud cover in December
San Diego, CA

Average cloud cover in December - San Diego, CA
  • Average cloud cover in December: 24

The month with the most cloud cover is December (Cloud cover 24).
The month with the least cloud cover is August (Cloud cover 9).

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Average visibility in December
San Diego, CA

Average visibility in December - San Diego, 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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