December weather forecast
San Clemente, CA

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Weather in December

The first month of the winter, December, is still a refreshing month in San Clemente, California, with an average temperature ranging between min 50.4°F (10.2°C) and max 62.6°F (17°C).

Temperature

The month of December, characterized by an average high of 62.6°F (17°C) and a low of 50.4°F (10.2°C), is recognized as the coldest.

Humidity

In San Clemente, the average relative humidity in December 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, in December, the average water temperature is 60.4°F (15.8°C).
Note: Swimming is not a pleasurable activity for the majority in water at 60.4°F (15.8°C). Breathing control gets harder as the water temperature dips from 69.8°F (21°C) to 59°F (15°C).

Daylight

The month with the shortest days is December, with an average of 10h and 0min of daylight.
On the first day of December in San Clemente, sunrise is at 6:36 am and sunset at 4:42 pm. On the last day of the month, sunrise is at 6:54 am and sunset at 4:53 pm PST.

Sunshine

December has the least sunshine of the year, 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 of 3 to 5 symbolizes a moderate health risk from exposure to the Sun's UV rays for ordinary individuals.
Note: A maximum UV index of 4 in December translates into the following recommendations:
Exercise prevention - Precautions against solar damage are endorsed. Avoiding the Sun during its peak radiation time around midday is a healthy practice. Sun-related eye harm can be minimized with proper sunglasses offering UVA and UVB coverage.
Updated: Jul 12, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What time of the year is the coldest in San Clemente?

December, recording an average high temperature of 62.6°F (17°C) and a low temperature of 50.4°F (10.2°C), is San Clemente's coldest month.

What is the average December temperature?

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

What is the average humidity in December?

The average relative humidity in December is 63%.

What is the rainiest month?

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.

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

In San Clemente, during December, the rain falls for 4.8 days and regularly aggregates up to 0.71" (18mm) of precipitation.

What is the ocean temperature in December?

In San Clemente, the average seawater temperature in December is 60.4°F (15.8°C). For most, swimming in 60.4°F (15.8°C) is not an enjoyable activity. Furthermore, controlling your breathing becomes progressively more difficult as the water temperature decreases from 69.8°F (21°C) to 59°F (15°C).

What is the month with the shortest days?

December has the shortest days of the year, with an average of 10h and 0min of daylight.

What is the average length of the day in December?

In December, the average day length is 9h and 59min.

When is the sunrise / sunset in December?

On the first day of December, sunrise is at 6:36 am and sunset at 4:42 pm. On the last day of the month, sunrise is at 6:54 am and sunset at 4:53 pm PST.

What is the month with the least sunshine?

With an average of 6.5h of sunshine, December has the least sunshine of the year.

How long on average sun shines in December?

The average sunshine duration in December is 6.5h.

What are the months with the lowest UV index?

The 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, the average daily maximum UV index in December is 4. A UV Index value of 3 to 5 symbolizes a moderate health threat from unprotected exposure to UV radiation.
Average humidity
Average rainfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in December
San Clemente, CA

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

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

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

Average wind speed in December
San Clemente, CA

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 - 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 - 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 - 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 - 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 / Average sunshine in December - San Clemente, CA
  • Average daylight in December: 10h and 0min

The month with the longest days is June (Average daylight: 14h and 18min).
The month with the shortest days is December (Average daylight: 10h and 0min).

  • Average sunshine in December: 6h and 3min

The months with the most sunshine are July and August (Average sunshine: 11h and 48min).
The month with the least sunshine is December (Average sunshine: 6h and 30min).

Average sunshine days in December
San Clemente, CA

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 - San Clemente, 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).

Average cloud cover in December
San Clemente, CA

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

The 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 - San Clemente, 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).

San Clemente, California, USA

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