San Diego
California, USA
Long-term weather forecast
Long-term weather forecast

December weather forecast and climate
San Diego, CA

The view of Coronado Island in San Diego, California, from across a water body on a sidewalk, with a row of palm trees
The view of Coronado Island in San Diego, California, from across a water body on a sidewalk, with a row of palm trees
December, the first month of the winter, in San Diego, is also an enjoyable 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 December, the average high-temperature is relatively the same as in November - an enjoyable 63.3°F (17.4°C). In San Diego, California, 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. Rain falls for 5.8 days and accumulates 1.65" (42mm) of precipitation.

Ocean temperature

In San Diego, in December, the average water temperature is 60.4°F (15.8°C).
Note: 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).

Daylight

The month with the shortest days in San Diego is December, with an average of 10h of daylight.

Sunshine

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

UV index

Months with the lowest UV index are January through March, November and December, with an average maximum UV index of 4. A UV Index value of 3 to 5 symbolizes a moderate health risk from the exposure to the Sun's UV radiation for average individuals.
Note: The daily maximum UV index of 4 interpret into the following advice:
Take precautions - Protection against the skin and eye damage is obliged. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects.

What is the temperature in December in San Diego?

The average high-temperature, in December, in San Diego, is 63.3°F (17.4°C), while the average low-temperature is 52.7°F (11.5°C).

What is the average humidity in December in San Diego?

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

How much does it rain in San Diego in December?

In San Diego, California, in December, it is raining for 5.8 days, with typically 1.65" (42mm) of accumulated precipitation.

What is the wettest month in San Diego?

The month with the most rainfall in San Diego, California, is December when the rain falls for 5.8 days and typically aggregates up to 1.65" (42mm) of precipitation.

What is the ocean temperature in December in San Diego?

In December, the average ocean temperature in San Diego, California, is 60.4°F (15.8°C). 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).

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

December has the shortest days of the year in San Diego, with an average of 10h of daylight.

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

In December, the average length of the day in San Diego is 10h.

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.

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

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

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

Months with the lowest UV index are January through March, November and December, with an average maximum UV index of 4.

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

In December, the average daily maximum UV index in San Diego, California, is 4. A UV Index of 3 to 5 symbolizes a medium hazard to health from the exposure to the Sun's UV rays.
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).

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%).

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 lowest rainfall) is June (0.12").

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 lowest number of rainy days is June (2.7 days).

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).

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

The month with the longest days is June (Average daylight: 14.3h).
The month with shortest days is December (Average daylight: 10h).

  • Average sunshine in December: 6.7h

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

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

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