December weather forecast
Opal Cliffs, CA

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Weather in December

December, the first month of the winter in Opal Cliffs, is also a moderate month, with an average temperature ranging between min 46.2°F (7.9°C) and max 57.2°F (14°C).

Temperature

December is the coldest month, exhibiting average temperatures of 57.2°F (14°C) at the peak and 46.2°F (7.9°C) at the base.

Humidity

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

Rainfall

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

Ocean temperature

In Opal Cliffs, in December, the average water temperature is 55.6°F (13.1°C).
Note: 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.

Daylight

December has the shortest days of the year, with an average of 9h and 42min of daylight.
On the first day of December in Opal Cliffs, sunrise is at 7:03 am and sunset at 4:51 pm. On the last day of the month, sunrise is at 7:20 am and sunset at 5:01 pm PST.

Sunshine

December has the least sunshine of the year, with an average of 5.8h of sunshine.

UV index

In Opal Cliffs, the average daily maximum UV index in December is 4. A UV Index estimate of 3 to 5 represents a medium health hazard from unprotected exposure to Sun's UV rays for ordinary individuals.
Note: In December, a regular UV index of 4 translates into these guidelines:
Heed the precautions - Suggestions to avoid sunburn are made. Around midday, solar radiation is most harmful; hence, exposure should be limited. Clothes that are both tight-knit and comfortably loose are prime choices for sun protection.
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Frequently asked questions

What is the coldest time of year in Opal Cliffs?

Temperature readings in Opal Cliffs, California, reach their annual highs in December, averaging 57.2°F (14°C) and a minimum average of 46.2°F (7.9°C).

What is the average December temperature in Opal Cliffs?

The high-temperature, in December, in Opal Cliffs, records 57.2°F (14°C), while the 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 in Opal Cliffs is 71%.

What is the wettest month in Opal Cliffs?

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

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

In Opal Cliffs, California, in December, it is raining for 10.3 days, with typically 2.8" (71mm) of accumulated precipitation.

What is the water temperature in December in Opal Cliffs?

In Opal Cliffs, California, 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 9h and 42min of daylight.

What is the average length of the day in December in Opal Cliffs?

The average day length in December in Opal Cliffs is 9h and 41min.

What time are sunrise and sunset in December in Opal Cliffs?

In December, on the first day of the month, sunrise is at 7:03 am and sunset at 4:51 pm. On the last day of the month, in Opal Cliffs, California, sunrise is at 7:20 am and sunset at 5:01 pm PST.

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, California.

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

In December, the average sunshine duration in Opal Cliffs, California, is 5.8h.

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

In December, the average daily maximum UV index in Opal Cliffs, California, is 4. A UV Index of 3 to 5 symbolizes a medium health risk 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
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"Hg

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

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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: 9h and 4min

The month with the longest days is June (Average daylight: 14h and 42min).
The month with the shortest days is December (Average daylight: 9h and 42min).

  • Average sunshine in December: 5h and 5min

The month with the most sunshine is July (Average sunshine: 11h and 42min).
The month with the least sunshine is December (Average sunshine: 5h and 48min).

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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

The months with the highest UV index are June, July, August and September (UV index 5).
The 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).
The 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

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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Opal Cliffs, California, USA

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