December weather forecast
Sea Ranch, CA

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Weather in December

December, the first month of the winter in Sea Ranch, is also a fresh month, with an average temperature varying between 39.9°F (4.4°C) and 54.7°F (12.6°C).

Temperature

In Sea Ranch, the lowest average temperatures are observed in December, with a high of 54.7°F (12.6°C) and a low of 39.9°F (4.4°C).

Humidity

The average relative humidity in December is 76%.

Rainfall

In Sea Ranch, during December, the rain falls for 11.8 days and regularly aggregates up to 3.54" (90mm) of precipitation. In Sea Ranch, during the entire year, the rain falls for 83.1 days and collects up to 21.38" (543mm) of precipitation.

Snowfall

January, March through December are months without snowfall.

Ocean temperature

In December, the average ocean temperature is 54°F (12.2°C).
Note: Diving into 54°F (12.2°C) when it's under 50°F (10°C) can cause immediate cold shock symptoms, marked by hyperventilation.

Daylight

December has the shortest days of the year, with an average of 9h and 30min of daylight.
On the first day of December, sunrise is at 7:13 am and sunset at 4:52 pm. On the last day of the month, sunrise is at 7:31 am and sunset at 5:02 pm PST.

Sunshine

With an average of 5.4h of sunshine, December has the least sunshine of the year.

UV index

February, November and December, with an average maximum UV index of 3, are months with the lowest UV index. A UV Index reading of 3 to 5 represents a medium vulnerability from exposure to the Sun's UV rays for average individuals.
Note: The average daily UV index of 3 in December transforms into the following instructions:
Guard yourself - Avoiding sunburn is suggested. Limiting exposure to the direct Sun during midday hours can help prevent harmful UV radiation effects. Sunglasses providing both UVA and UVB protection are non-negotiable on sunlit days.
Updated: Jul 20, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What month is the coldest?

In Sea Ranch, December is the coldest month, with temperatures averaging a high of 54.7°F (12.6°C) and a low of 39.9°F (4.4°C).

What is the average December temperature?

During December, Sea Ranch experiences an average high-temperature of 54.7°F (12.6°C) and a low-temperature of 39.9°F (4.4°C). The average heat index (a.k.a. 'apparent temperature', 'feels like'), which factors the actual air temperature with the relative humidity, in August is computed to be 87.8°F (31°C).

What is the average humidity in December?

In December, the average relative humidity is 76%.

How many days does it rain in December?

In Sea Ranch, in December, during 11.8 rainfall days, 3.54" (90mm) of precipitation is typically accumulated.

When it does not snow?

January, March through December are months without snowfall.

What is the ocean temperature in December?

In December, the average ocean temperature is 54°F (12.2°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?

The month with the shortest days is December, with an average of 9h and 30min of daylight.

What is the average length of the day in December?

In December, the average day length is 9h and 31min.

When is the sunrise / sunset in December?

On the first day of December, sunrise is at 7:13 am and sunset at 4:52 pm. On the last day of the month, sunrise is at 7:31 am and sunset at 5:02 pm PST.

What is the month with the least sunshine?

The month with the least sunshine is December, with an average of 5.4h of sunshine.

How long on average sun shines in December?

In December, the average sunshine duration is 5.4h.

What are the months with the lowest UV index in Sea Ranch?

February, November and December, with an average maximum UV index of 3, are months with the lowest UV index.

What is the UV index intensity in December?

In December, the average daily maximum UV index is 3. A UV Index reading of 3 to 5 represents a moderate vulnerability from exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in December
Sea Ranch, CA

Average temperature in December - Sea Ranch, CA
  • Average high temperature in December: 54.7°F

The warmest month (with the highest average high temperature) is August (83.5°F).
The month with the lowest average high temperature is December (54.7°F).

  • Average low temperature in December: 39.9°F

The month with the highest average low temperature is August (54.1°F).
The coldest month (with the lowest average low temperature) is December (39.9°F).

Average pressure in December
Sea Ranch, CA

Average pressure in December - Sea Ranch, CA
  • Average pressure in December: 30.1"Hg

The month with the highest atmospheric pressure is January (30.13"Hg).
The months with the lowest atmospheric pressure are June, August and September (29.92"Hg).

Average wind speed in December
Sea Ranch, CA

Average wind speed in December - Sea Ranch, CA
  • Average wind speed in December: 5.2mph

The windiest month (with the highest average wind speed) is May (6.8mph).
The calmest month (with the lowest average wind speed) is November (4.9mph).

Average humidity in December
Sea Ranch, CA

Average humidity in December - Sea Ranch, CA
  • Average humidity in December: 76%

The month with the highest relative humidity is March (78%).
The months with the lowest relative humidity are July and September (60%).

Average rainfall in December
Sea Ranch, CA

Average rainfall in December - Sea Ranch, CA
  • Average rainfall in December: 3.54"

The wettest month (with the highest rainfall) is February (4.49").
The driest months (with the least rainfall) are July and August (0.04").

Average rainfall days in December
Sea Ranch, CA

Average rainfall days in December - Sea Ranch, CA
  • Average rainfall days in December: 11.8 days

The month with the highest number of rainy days is March (15 days).
The month with the least rainy days is August (0.9 days).

Average snowfall in December
Sea Ranch, CA

Average snowfall in December - Sea Ranch, CA
  • Average snowfall in December: 0"

The month with the highest snowfall is February (0.2").
The months with the least snowfall are January, March, April, May, June, July, August, September, October, November and December (0").

Average snowfall days in December
Sea Ranch, CA

Average snowfall days in December - Sea Ranch, CA
  • Average snowfall days in December: 0 days

The month with the highest number of snowfall days is February (0.3 days).
The months with the least snowfall days are January, March, April, May, June, July, August, September, October, November and December (0 days).

Average sea temperature in December
Sea Ranch, CA

Average sea temperature in December - Sea Ranch, CA
  • Average sea temperature in December: 54°F

The best month for swimming (with the highest average sea temperature) is October (56°F).
The coldest month (with the lowest average sea temperature) is June (51.9°F).

Average daylight in December /
Average sunshine in December
Sea Ranch, CA

Average daylight in December / Average sunshine in December - Sea Ranch, CA
  • Average daylight in December: 9h and 3min

The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 30min).

  • Average sunshine in December: 5h and 2min

The months with the most sunshine are July and August (Average sunshine: 12h and 0min).
The month with the least sunshine is December (Average sunshine: 5h and 24min).

Average sunshine days in December
Sea Ranch, CA

Average sunshine days in December - Sea Ranch, CA
  • Average sunshine days in December: 17.5 days

The months with the most sunshine days are July and August (29.6 days).
The month with the least sunshine days is March (14.6 days).

Average UV index in December
Sea Ranch, CA

Average UV index in December - Sea Ranch, CA
  • Average UV index in December: 3

The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are February, November and December (UV index 3).

Average cloud cover in December
Sea Ranch, CA

Average cloud cover in December - Sea Ranch, CA
  • Average cloud cover in December: 40

The month with the most cloud cover is March (Cloud cover 42).
The months with the least cloud cover are July and August (Cloud cover 6).

Average visibility in December
Sea Ranch, CA

Average visibility in December - Sea Ranch, 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).

Sea Ranch, California, USA

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