December weather forecast and climate
Oakley, CA

Weather in December

The first month of the winter, December, is still a cool month in Oakley, California, with temperature in the range of an average low of 41.7°F (5.4°C) and an average high of 55°F (12.8°C).

Temperature

With an average high-temperature of 55°F (12.8°C) and an average low-temperature of 41.7°F (5.4°C), December is the coldest month.

Humidity

The average relative humidity in Oakley is 71%.

Rainfall

In Oakley, during 9.3 rainfall days, 1.57" (40mm) of precipitation is typically accumulated. Throughout the year, there are 62 rainfall days, and 10.16" (258mm) of precipitation is accumulated.

Snowfall

December is the only month when snow falls in Oakley. December has the most snowfall days of the year. Snow falls for 0.1 days.

Daylight

The month with the shortest days in Oakley is December, with an average of 9.6h of daylight.

Sunshine

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

UV index

Months with the lowest UV index in Oakley are January, February, November and December, with an average maximum UV index of 3. A UV Index estimate of 3 to 5 represents a moderate health risk from the exposure to the Sun's UV rays for average individuals.
Note: The daily maximum UV index of 3 interpret into the following advice:
Take precautions - Protection against sunburn is recommended. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes. Beware! The strength of the UV rays is increased nearly double-fold by the reflection of the snow.
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FAQ

What is the coldest month in Oakley?

December is the coldest month, with an average high-temperature of 55°F (12.8°C) and an average low-temperature of 41.7°F (5.4°C).

What is the temperature in December in Oakley?

The average high-temperature, in December, in Oakley, is 55°F (12.8°C), while the average low-temperature is 41.7°F (5.4°C).

What is the average humidity in December in Oakley?

The average relative humidity in December is 71%.

How much does it rain in Oakley in December?

In Oakley, in December, during 9.3 rainfall days, 1.57" (40mm) of precipitation is typically accumulated.

When does it start to snow in Oakley?

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

When does it snow the most in Oakley?

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

What is the month with the shortest days in Oakley?

With an average of 9.6h of daylight, December has the shortest days of the year in Oakley, California.

What is the average length of the day in December in Oakley?

In Oakley, the average length of the day in December is 9.6h.

What is the month with the least sunshine in Oakley?

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

How long on average sun shines in December in Oakley?

The average sunshine in December is 5.8h.

When is the lowest UV index in Oakley?

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

What is the UV index reading in December in Oakley?

In Oakley, the average daily maximum UV index in December is 3. A UV Index of 3 to 5 symbolizes a moderate health threat from the exposure to the Sun's UV rays.

Average temperature in December
Oakley, CA

Average temperature in December - Oakley, 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).

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Average pressure in December
Oakley, CA

Average pressure in December - Oakley, CA
  • Average pressure in December: 30.11"

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

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Average wind speed in December
Oakley, CA

Average wind speed in December - Oakley, 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).

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Average humidity in December
Oakley, CA

Average humidity in December - Oakley, 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%).

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Average rainfall in December
Oakley, CA

Average rainfall in December - Oakley, 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").

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Average rainfall days in December
Oakley, CA

Average rainfall days in December - Oakley, 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).

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Average snowfall days in December
Oakley, CA

Average snowfall days in December - Oakley, CA
  • Average snowfall days in December: 0.1 days

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

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Average daylight in December /
Average sunshine in December
Oakley, CA

Average daylight in December / Average sunshine in December - Oakley, CA
  • Average daylight in December: 9.6h

The month with the longest days is June (Average daylight: 14.8h).
The month with the shortest days is December (Average daylight: 9.6h).

  • Average sunshine in December: 5.8h

The month with the most sunshine is July (Average sunshine: 12.1h).
The month with the least sunshine is December (Average sunshine: 5.8h).

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Average sunshine days in December
Oakley, CA

Average sunshine days in December - Oakley, 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).

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Average UV index in December
Oakley, CA

Average UV index in December - Oakley, CA
  • Average UV index in December: 3

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

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Average cloud cover in December
Oakley, CA

Average cloud cover in December - Oakley, CA
  • Average cloud cover in December: 35

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).

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Average visibility in December
Oakley, CA

Average visibility in December - Oakley, CA
  • Average visibility in December: 6mi

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

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