December weather forecast
O'Brien, CA

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Weather in December

December, the first month of the winter in O'Brien, is still a chilly month, with an average temperature ranging between max 47.8°F and min 33.6°F.

Temperature

December, marked by an average high-temperature of 47.8°F and a low-temperature of 33.6°F, is the coldest month.

Humidity

The average relative humidity in December is 74%.

Rainfall

In December, in O'Brien, the rain falls for 12.7 days. Throughout December, 3.5" of precipitation is accumulated. In O'Brien, during the entire year, the rain falls for 102.3 days and collects up to 24.21" of precipitation.

Snowfall

Months with snowfall in O'Brien are January through March, November and December. In O'Brien, during December, snow falls for 1 days and regularly aggregates up to 1.1" of snow. In O'Brien, during the entire year, snow falls for 4.6 days and aggregates up to 4.45" of snow.

Daylight

With an average of 9h and 18min of daylight, December has the shortest days of the year.
On the first day of December in O'Brien, California, sunrise is at 7:14 am and sunset at 4:42 pm. On the last day of the month, sunrise is at 7:33 am and sunset at 4:51 pm PST.

Sunshine

With an average of 5.3h of sunshine, December has the least sunshine of the year in O'Brien, California.

UV index

February, November and December, with an average maximum UV index of 2, are months with the lowest UV index. A UV Index value of 2, and less, symbolizes a low health risk from unsafe exposure to UV radiation for the ordinary person.
Note: During December, 2 as the daily maximum UV index converts into the following advice:
People with sensitive skin, children, and babies should always be protected from prolonged sun exposure. Avoiding the Sun's peak radiation during midday hours is essential for health and safety. On days when the sun blazes, arm yourself with sunglasses that block UVA and UVB radiation. Keep in mind! Snow's reflective quality can nearly double the intensity of the Sun's UV radiation.
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FAQ

What month is the coldest in O'Brien?

O'Brien's coldest month, December, generally records average temperatures ranging from a high of 47.8°F to a low of 33.6°F.

What is the average December temperature in O'Brien?

The high-temperature in O'Brien during December is 47.8°F and the low-temperature is 33.6°F. In September, the average heat index (a.k.a. 'felt air temperature', 'feels like'), which takes the relative humidity and factors it into the air temperature reading, is estimated at 84.2°F.

What is the average humidity in December in O'Brien?

In O'Brien, California, the average relative humidity in December is 74%.

How many days does it rain in December in O'Brien?

In O'Brien, during December, the rain falls for 12.7 days and regularly aggregates up to 3.5" of precipitation.

How much does it snow in O'Brien in December?

In December, in O'Brien, California, it is snowing for 1 days. Throughout December, 1.1" of snow is accumulated.

What is the month with the shortest days in O'Brien?

December has the shortest days of the year in O'Brien, with an average of 9h and 18min of daylight.

What is the average length of the day in December in O'Brien?

The average day length in December in O'Brien, California, is 9h and 18min.

What time are sunrise and sunset in December in O'Brien?

In December, on the first day of the month, sunrise is at 7:14 am and sunset at 4:42 pm. On the last day of the month, in O'Brien, California, sunrise is at 7:33 am and sunset at 4:51 pm PST.

What is the month with the least sunshine in O'Brien?

The month with the least sunshine is December, with an average of 5.3h of sunshine.

How long on average sun shines in December in O'Brien?

The average sunshine duration in December in O'Brien is 5.3h.

What are the months with the lowest UV index in O'Brien?

February, November and December, with an average maximum UV index of 2, are months with the lowest UV index.

What is the UV index intensity in December in O'Brien?

The average daily maximum UV index in December in O'Brien is 2. A UV Index estimate of 2, and below, represents a low health risk from exposure to Sun's UV rays.
Average high temperature
Average low temperature
Average pressure
Average wind speed
Average max. wind speed
Average wind speed gusts
Average humidity
Average rainfall
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
O'Brien, CA

Average temperature in December - O
  • Average high temperature in December: 47.8°F

The warmest month (with the highest average high temperature) is July (91.6°F).
The month with the lowest average high temperature is December (47.8°F).

  • Average low temperature in December: 33.6°F

The month with the highest average low temperature is July (59.4°F).
The coldest month (with the lowest average low temperature) is December (33.6°F).

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Average pressure in December
O'Brien, CA

Average pressure in December - O
  • Average pressure in December: 30.14"Hg

The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is August (29.92"Hg).

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Average wind speed in December
O'Brien, CA

Average wind speed in December - O
  • Average wind speed in December: 4.7mph

The windiest months (with the highest average wind speed) are March and October (5.3mph).
The calmest months (with the lowest average wind speed) are August and November (4.5mph).

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Average humidity in December
O'Brien, CA

Average humidity in December - O
  • Average humidity in December: 74%

The month with the highest relative humidity is March (77%).
The month with the lowest relative humidity is August (37%).

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Average rainfall in December
O'Brien, CA

Average rainfall in December - O
  • Average rainfall in December: 3.5"

The wettest month (with the highest rainfall) is March (4.8").
The driest month (with the least rainfall) is July (0.12").

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Average rainfall days in December
O'Brien, CA

Average rainfall days in December - O
  • Average rainfall days in December: 12.7 days

The month with the highest number of rainy days is March (16.8 days).
The month with the least rainy days is August (1.7 days).

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Average snowfall in December
O'Brien, CA

Average snowfall in December - O
  • Average snowfall in December: 1.1"

The month with the highest snowfall is November (1.3").
The months with the least snowfall are April, May, June, July, August, September and October (0").

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Average snowfall days in December
O'Brien, CA

Average snowfall days in December - O
  • Average snowfall days in December: 1 days

The month with the highest number of snowfall days is February (1.9 days).
The months with the least snowfall days are April, May, June, July, August, September and October (0 days).

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Average daylight in December /
Average sunshine in December
O'Brien, CA

Average daylight in December / Average sunshine in December - O
  • Average daylight in December: 9h and 2min

The month with the longest days is June (Average daylight: 15h and 6min).
The month with the shortest days is December (Average daylight: 9h and 18min).

  • Average sunshine in December: 5h and 2min

The month with the most sunshine is July (Average sunshine: 12h and 12min).
The month with the least sunshine is December (Average sunshine: 5h and 18min).

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Average sunshine days in December
O'Brien, CA

Average sunshine days in December - O
  • Average sunshine days in December: 15.7 days

The month with the most sunshine days is August (27.1 days).
The month with the least sunshine days is March (11.8 days).

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Average UV index in December
O'Brien, CA

Average UV index in December - O
  • Average UV index in December: 2

The month with the highest UV index is July (UV index 7).
The months with the lowest UV index are February, November and December (UV index 2).

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Average cloud cover in December
O'Brien, CA

Average cloud cover in December - O
  • Average cloud cover in December: 41

The month with the most cloud cover is March (Cloud cover 44).
The month with the least cloud cover is August (Cloud cover 5).

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Average visibility in December
O'Brien, CA

Average visibility in December - O
  • Average visibility in December: 5mi

The months with the highest visibility are January, February, March, April, May, June, July, August, September, October and November (6mi).
The month with the lowest visibility is December (5mi).

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O'Brien, California, USA

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