December weather forecast
Bethel Island, CA

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Weather in December

December, the first month of the winter in Bethel Island, is still a cool month, with an average temperature ranging between max 55°F (12.8°C) and min 41.7°F (5.4°C).

Temperature

December proves to be the coldest month, recording an average maximum temperature of 55°F (12.8°C) and a minimum temperature of 41.7°F (5.4°C).

Humidity

In December, the average relative humidity is 71%.

Rainfall

In Bethel Island, in December, during 9.3 rainfall days, 1.57" (40mm) of precipitation is typically accumulated. In Bethel Island, during the entire year, the rain falls for 62 days and collects up to 10.16" (258mm) of precipitation.

Snowfall

The only month with snowfall is December. The month with the most snowfall days is December, when snow falls for 0.1 days.

Daylight

With an average of 9h and 36min of daylight, December has the shortest days of the year.
On the first day of the month, sunrise is at 7:04 am and sunset at 4:47 pm. On the last day of December, sunrise is at 7:22 am and sunset at 4:57 pm PST.

Sunshine

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

UV index

The months with the lowest UV index are January, February, November and December, with an average maximum UV index of 3. A UV Index value of 3 to 5 symbolizes a moderate threat to health from exposure to the Sun's UV radiation for the ordinary person.
Note: The maximum daily UV index, 3 in December, converts into the following recommendations:
Take precautions - Protection against skin and eye damage is obliged. When the Sun is at its strongest around midday, find shade and limit exposure. Sun protection is enhanced with clothing that boasts a tight weave yet offers a loose fit. Take careful note! The UV radiation of the Sun can be nearly doubled by snow reflection.

Frequently asked questions

What is the coldest month?

In Bethel Island, the lowest temperatures are generally noted in December, averaging a high of 55°F (12.8°C) and a low of 41.7°F (5.4°C).

What is the average December temperature?

Bethel Island in December has an average high-temperature of 55°F (12.8°C) and an average low-temperature of 41.7°F (5.4°C). In September, the average heat index (a.k.a. 'feels like', 'real feel'), which combines relative humidity and air temperature, is computed to be 87.8°F (31°C).

What is the average humidity in December?

The average relative humidity in December is 71%.

How many days does it rain in December?

In Bethel Island, during December, the rain falls for 9.3 days and regularly aggregates up to 1.57" (40mm) of precipitation.

What is the snowiest month?

December has the most snowfall days of the year. Snow falls for 0.1 days.

When does it start snowing?

December is the first month it typically snows in Bethel Island. Throughout December, there are 0.1 snowfall days.

What is the month with the shortest days?

The month with the shortest days is December, with an average of 9h and 36min of daylight.

What is the average length of the day in December?

In December, the average day length is 9h and 35min.

When are sunrise and sunset in December?

In December, on the first day of the month, sunrise is at 7:04 am and sunset at 4:47 pm. On the last day of the month, sunrise is at 7:22 am and sunset at 4:57 pm PST.

What is the month with the least sunshine?

The month with the least sunshine in Bethel Island is December, with an average of 5.8h of sunshine.

How long on average sun shines in December?

In December, the average sunshine duration in Bethel Island is 5.8h.

What is the month with the lowest UV index?

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

What is the UV index intensity in December?

The average daily maximum UV index in December is 3. A UV Index of 3 to 5 symbolizes a medium hazard to health from unsafe exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in December
Bethel Island, CA

Average temperature in December - Bethel Island, CA
  • Average high temperature in December: 55°F

The warmest month (with the highest average high temperature) is July (88.5°F).
The month with the lowest average high temperature is December (55°F).

  • Average low temperature in December: 41.7°F

The month with the highest average low temperature is September (57.7°F).
The coldest month (with the lowest average low temperature) is January (41.5°F).

Average pressure in December
Bethel Island, CA

Average pressure in December - Bethel Island, CA
  • Average pressure in December: 30.11"Hg

The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).

Average wind speed in December
Bethel Island, CA

Average wind speed in December - Bethel Island, CA
  • Average wind speed in December: 5mph

The windiest month (with the highest average wind speed) is June (7.8mph).
The calmest months (with the lowest average wind speed) are January and November (4.5mph).

Average humidity in December
Bethel Island, CA

Average humidity in December - Bethel Island, CA
  • Average humidity in December: 71%

The month with the highest relative humidity is January (74%).
The month with the lowest relative humidity is September (52%).

Average rainfall in December
Bethel Island, CA

Average rainfall in December - Bethel Island, CA
  • Average rainfall in December: 1.57"

The wettest month (with the highest rainfall) is February (2.09").
The driest months (with the least rainfall) are July and August (0.04").

Average rainfall days in December
Bethel Island, CA

Average rainfall days in December - Bethel Island, CA
  • Average rainfall days in December: 9.3 days

The month with the highest number of rainy days is March (12.3 days).
The month with the least rainy days is August (0.8 days).

Average snowfall days in December
Bethel Island, CA

Average snowfall days in December - Bethel Island, CA
  • Average snowfall days in December: 0.1 days

The month with the highest number of snowfall days is December (0.1 days).
The months with the least snowfall days are January, February, March, April, May, June, July, August, September, October and November (0 days).

Average daylight in December /
Average sunshine in December
Bethel Island, CA

Average daylight in December / Average sunshine in December - Bethel Island, CA
  • Average daylight in December: 9h and 4min

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 36min).

  • Average sunshine in December: 5h and 5min

The month with the most sunshine is July (Average sunshine: 12h and 6min).
The month with the least sunshine is December (Average sunshine: 5h and 48min).

Average sunshine days in December
Bethel Island, CA

Average sunshine days in December - Bethel Island, CA
  • Average sunshine days in December: 21.1 days

The month with the most sunshine days is August (29.8 days).
The month with the least sunshine days is March (17.7 days).

Average UV index in December
Bethel Island, CA

Average UV index in December - Bethel Island, 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 January, February, November and December (UV index 3).

Average cloud cover in December
Bethel Island, CA

Average cloud cover in December - Bethel Island, CA
  • Average cloud cover in December: 35

The months with the most cloud cover are March and December (Cloud cover 35).
The month with the least cloud cover is July (Cloud cover 5).

Average visibility in December
Bethel Island, CA

Average visibility in December - Bethel Island, 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).

Bethel Island, California, USA

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