December weather forecastOpal Cliffs, CA
December
Weather in December
December, the first month of the winter in Opal Cliffs, is still a mild month, with temperature in the range of an average low of 46.2°F (7.9°C) and an average high of 57.2°F (14°C).Temperature
Opal Cliffs's coldest weather arrives in December, when temperatures average a high of 57.2°F (14°C) and a low of 46.2°F (7.9°C).Humidity
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 December, the average ocean temperature is 55.6°F (13.1°C).Note: Staying in 55.6°F (13.1°C) waters for just a few moments at 55.4°F (13°C) can be harrowing, and below 50°F (10°C) poses breathing and cold shock risks, depending on individual tolerance.
Daylight
The month with the shortest days is December, with an average of 9h and 42min of daylight.On the first day of December, 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
The month with the least sunshine is December, with an average of 5.8h of sunshine.UV index
In December, the average daily maximum UV index is 4. A UV Index of 3 to 5 symbolizes a moderate health risk from exposure to the Sun's UV radiation for the average person.Note: In December, a daily maximum UV index of 4 leads to the following instructions:
Preventative actions are necessary - Recommendations to ward off sunburn are given. Solar radiation is at its peak intensity during midday, so it's advisable to stay indoors or in the shade. In bright sunlight, prioritize sunglasses that grant protection from UVA and UVB radiation.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
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).
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).
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).
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%).
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").
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).
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).
Average daylight in December /
Average sunshine in December
Opal Cliffs, CA
- Average daylight in December: 9h and 42min
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 48min
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).
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).
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).
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).
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).
