December weather forecast and climate
San Clemente, CA

The first month of the winter, December, is also an enjoyable month in San Clemente, California, with average temperature varying between 62.6°F (17°C) and 50.4°F (10.2°C).

Temperature

With an average high-temperature of 62.6°F (17°C) and an average low-temperature of 50.4°F (10.2°C), December is the coldest month.

Humidity

In December, the average relative humidity in San Clemente is 63%.

Rainfall

December is the month with the most rainfall. Rain falls for 4.8 days and accumulates 0.71" (18mm) of precipitation.

Ocean temperature

In San Clemente, the average seawater 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 is December, with an average of 10h of daylight.

Sunshine

December has the least sunshine of the year in San Clemente, with an average of 6.5h 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 reading of 3 to 5 represents a moderate threat to health from the exposure to the Sun's UV rays for the ordinary person.
Note: In December, the average maximum UV index of 4 translate into the following recommendations:
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. 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.

What is the coldest month in San Clemente?

The coldest month in San Clemente is December, with an average high-temperature of 62.6°F (17°C) and an average low-temperature of 50.4°F (10.2°C).

What is the temperature in December in San Clemente?

The average high-temperature, in December, is 62.6°F (17°C), while the average low-temperature is 50.4°F (10.2°C).

What is the average humidity in December in San Clemente?

In December, the average relative humidity in San Clemente, California, is 63%.

How much does it rain in San Clemente in December?

In San Clemente, in December, during 4.8 rainfall days, 0.71" (18mm) of precipitation is typically accumulated.

What is the rainiest month in San Clemente?

The month with the most rainfall in San Clemente is December when the rain falls for 4.8 days and typically aggregates up to 0.71" (18mm) of precipitation.

What is the ocean temperature in December in San Clemente?

In December, the average ocean temperature 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 Clemente?

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

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

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

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

The month with the least sunshine is December, with an average of 6.5h of sunshine.

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

In December, the average sunshine in San Clemente is 6.5h.

What are the months with the lowest UV index in San Clemente?

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

How high is the UV index in December in San Clemente?

In San Clemente, the average daily maximum UV index in December is 4. A UV Index estimate of 3 to 5 represents a medium hazard to health from the exposure to the Sun's UV rays.
Average temperature in December - San Clemente, CA
  • Average high temperature in December: 62.6°F

The warmest month (with the highest average high temperature) is September (77.4°F).
The month with the lowest average high temperature is December (62.6°F).

  • Average low temperature in December: 50.4°F

Months with the highest average low temperature are August and September (63.5°F).
The coldest month (with the lowest average low temperature) is February (49.6°F).

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

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

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

The windiest month (with the highest average wind speed) is April (6.2mph).
The calmest months (with the lowest average wind speed) are August and September (4.9mph).

Average humidity in December - San Clemente, CA
  • Average humidity in December: 63%

The month with the highest relative humidity is June (75%).
The month with the lowest relative humidity is November (60%).

Average rainfall in December - San Clemente, CA
  • Average rainfall in December: 0.71"

The wettest month (with the highest rainfall) is December (0.71").
The driest month (with the least rainfall) is June (0.08").

Average rainfall days in December - San Clemente, CA
  • Average rainfall days in December: 4.8 days

The month with the highest number of rainy days is March (7.3 days).
The month with the least rainy days is June (1.4 days).

Average sea temperature in December - San Clemente, CA
  • Average sea temperature in December: 60.3°F

The best month for swimming (with the highest average sea temperature) is August (68.3°F).
The coldest months (with the lowest average sea temperature) are January and February (58.9°F).

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

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

  • Average sunshine in December: 6.5h

Months with the most sunshine are July and August (Average sunshine: 11.8h).
The month with the least sunshine is December (Average sunshine: 6.5h).

Average sunshine days in December - San Clemente, CA
  • Average sunshine days in December: 24.3 days

The month with the most sunshine days is October (26 days).
The month with the least sunshine days is February (21.6 days).

Average UV index in December - San Clemente, 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).

Average cloud cover in December - San Clemente, CA
  • Average cloud cover in December: 26

Months with the most cloud cover are March and May (Cloud cover 27).
The month with the least cloud cover is August (Cloud cover 11).

Average visibility in December - San Clemente, CA
  • Average visibility in December: 6mi

Months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
Months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).