December weather forecast and climate
Opal Cliffs, CA

Weather in December

December, the first month of the winter, in Opal Cliffs, is still a mild month, with average temperature fluctuating between 46.2°F (7.9°C) and 57.2°F (14°C).

Temperature

December is the coldest month, with an average high-temperature of 57.2°F (14°C) and an average low-temperature of 46.2°F (7.9°C).

Humidity

In December, the average relative humidity in Opal Cliffs is 71%.

Rainfall

December is the month with the most rainfall in Opal Cliffs. Rain falls for 10.3 days and accumulates 2.8" (71mm) of precipitation.

Ocean temperature

In Opal Cliffs, the average water temperature is 55.6°F (13.1°C).
Note: Swimming in 55.6°F (13.1°C) is considered dangerous. Unprotected immersion in temperatures below 50°F (10°C) causes quickly maximum intensity cold shock with hyperventilation.

Daylight

December has the shortest days of the year, with an average of 9.7h of daylight.

Sunshine

The month with the least sunshine in Opal Cliffs, California, is December, with an average of 5.8h of sunshine.

UV index

The average daily maximum UV index in December is 4. A UV Index of 3 to 5 symbolizes a medium health hazard from unprotected exposure to the Sun's UV rays for the ordinary person.
Note: The average daily UV index of 4 transform into the following instructions:
Take precautions - Protection against sunburn is recommended. 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.
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FAQ

What is the coldest month in Opal Cliffs?

December is the coldest month in Opal Cliffs, California, with an average high-temperature of 57.2°F (14°C) and an average low-temperature of 46.2°F (7.9°C).

What is the temperature in December in Opal Cliffs?

In Opal Cliffs, California, in December, the average high-temperature is 57.2°F (14°C), and the average low-temperature is 46.2°F (7.9°C).

What is the average humidity in December in Opal Cliffs?

In December, the average relative humidity is 71%.

How many days does it rain in December in Opal Cliffs?

In Opal Cliffs, during December, the rain falls for 10.3 days and regularly aggregates up to 2.8" (71mm) of precipitation.

What is the wettest month in Opal Cliffs?

The month with the most rainfall in Opal Cliffs is December when the rain falls for 10.3 days and typically aggregates up to 2.8" (71mm) of precipitation.

What is the ocean temperature in December in Opal Cliffs?

In Opal Cliffs, in December, the average water temperature is 55.6°F (13.1°C). At temperatures below 50°F (10°C), swimming in a suitably protected swimsuit is feasible; otherwise, cold shock and loss of breathing control are imminent. Even a short swim, without thermal protection, at temperatures around 55.4°F (13°C) is not comfortable.

What is the month with the shortest days in Opal Cliffs?

The month with the shortest days in Opal Cliffs is December, with an average of 9.7h of daylight.

How many hours of daylight does Opal Cliffs have in December?

In December, the average length of the day in Opal Cliffs is 9.7h.

What is the month with the least sunshine in Opal Cliffs?

With an average of 5.8h of sunshine, December has the least sunshine of the year in Opal Cliffs.

How long on average sun shines in December in Opal Cliffs?

In December, the average sunshine is 5.8h.

What is the UV index intensity in December in Opal Cliffs?

The average daily maximum UV index in December in Opal Cliffs, California, is 4. A UV Index reading of 3 to 5 represents a medium health risk from the exposure to the Sun's UV radiation.

Average temperature in December
Opal Cliffs, CA

Average temperature in December - Opal Cliffs, CA
  • Average high temperature in December: 57.2°F

The warmest months (with the highest average high temperature) are August and September (73°F).
The month with the lowest average high temperature is December (57.2°F).

  • Average low temperature in December: 46.2°F

The month with the highest average low temperature is September (55.2°F).
The coldest month (with the lowest average low temperature) is February (45.5°F).

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Average pressure in December
Opal Cliffs, CA

Average pressure in December - Opal Cliffs, CA
  • Average pressure in December: 30.11"

The month with the highest atmospheric pressure is January (30.13").
The month with the lowest atmospheric pressure is September (29.92").

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Average wind speed in December
Opal Cliffs, CA

Average wind speed in December - Opal Cliffs, CA
  • Average wind speed in December: 6.2mph

The windiest month (with the highest average wind speed) is April (7.4mph).
The calmest months (with the lowest average wind speed) are July and August (5.5mph).

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Average humidity in December
Opal Cliffs, CA

Average humidity in December - Opal Cliffs, 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 (68%).

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Average rainfall in December
Opal Cliffs, CA

Average rainfall in December - Opal Cliffs, CA
  • Average rainfall in December: 2.8"

The wettest month (with the highest rainfall) is December (2.8").
The driest months (with the least rainfall) are July and August (0.04").

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Average rainfall days in December
Opal Cliffs, CA

Average rainfall days in December - Opal Cliffs, CA
  • Average rainfall days in December: 10.3 days

The month with the highest number of rainy days is March (13.4 days).
The month with the least rainy days is August (1.2 days).

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Average sea temperature in December
Opal Cliffs, CA

Average sea temperature in December - Opal Cliffs, CA
  • Average sea temperature in December: 55.6°F

The best months for swimming (with the highest average sea temperature) are August and September (58.1°F).
The coldest month (with the lowest average sea temperature) is April (53.8°F).

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Average daylight in December /
Average sunshine in December
Opal Cliffs, CA

Average daylight in December / Average sunshine in December - Opal Cliffs, CA
  • Average daylight in December: 9.7h

The month with the longest days is June (Average daylight: 14.7h).
The month with the shortest days is December (Average daylight: 9.7h).

  • Average sunshine in December: 5.8h

The month with the most sunshine is July (Average sunshine: 11.7h).
The month with the least sunshine is December (Average sunshine: 5.8h).

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Average sunshine days in December
Opal Cliffs, CA

Average sunshine days in December - Opal Cliffs, CA
  • Average sunshine days in December: 19.5 days

The month with the most sunshine days is August (27.8 days).
The month with the least sunshine days is March (16.4 days).

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Average UV index in December
Opal Cliffs, CA

Average UV index in December - Opal Cliffs, CA
  • Average UV index in December: 4

Months with the highest UV index are June, July, August and September (UV index 5).
Months with the lowest UV index are February and November (UV index 3).

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Average cloud cover in December
Opal Cliffs, CA

Average cloud cover in December - Opal Cliffs, CA
  • Average cloud cover in December: 35

The month with the most cloud cover is March (Cloud cover 38).
Months with the least cloud cover are July and September (Cloud cover 15).

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Average visibility in December
Opal Cliffs, CA

Average visibility in December - Opal Cliffs, 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).

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