December weather forecast and climate
Onyx, CA

Weather in December

The first month of the winter, December, is still a chilly month in Onyx, California, with average temperature fluctuating between 48.7°F (9.3°C) and 30.9°F (-0.6°C).

Temperature

December is the coldest month, with an average high-temperature of 48.7°F (9.3°C) and an average low-temperature of 30.9°F (-0.6°C).

Humidity

In December, the average relative humidity is 57%.

Rainfall

In Onyx, during 7.3 rainfall days, 1.89" (48mm) of precipitation is typically accumulated. In Onyx, during the entire year, the rain falls for 61 days and collects up to 11.81" (300mm) of precipitation.

Snowfall

Months with snowfall are January through April, November and December. In Onyx, during 1.5 snowfall days, 0.71" (18mm) of snow is typically accumulated. In Onyx, California, during the entire year, snow falls for 9.1 days, and aggregates up to 9.13" (232mm) of snow.

Daylight

With an average of 9.8h of daylight, December has the shortest days of the year.

Sunshine

Months with the least sunshine in Onyx are January, February and December, with an average of 6.7h of sunshine.

UV index

February, November and December, with an average maximum UV index of 2, are months with the lowest UV index. A UV Index estimate of 2, and below, represents a minimal health vulnerability from the exposure to the Sun's UV radiation for average individuals.
Note: In December, the average maximum UV index of 2 translate into the following recommendations:
People with sensitive skin, children, and babies should always be protected from prolonged sun exposure. 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. Caution! The reflection of snow can nearly double the intensity of the Sun's UV radiation.
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FAQ

What is the coldest month in Onyx?

With an average high-temperature of 48.7°F (9.3°C) and an average low-temperature of 30.9°F (-0.6°C), December is the coldest month.

What is the temperature in December in Onyx?

In Onyx, in December, the average high-temperature is 48.7°F (9.3°C), and the average low-temperature is 30.9°F (-0.6°C).

What is the average humidity in December in Onyx?

The average relative humidity in December is 57%.

How much does it rain in Onyx in December?

In Onyx, California, in December, during 7.3 rainfall days, 1.89" (48mm) of precipitation is typically accumulated.

How much does it snow in Onyx in December?

In Onyx, in December, snow falls for 1.5 days, with typically accumulated 0.71" (18mm) of snow.

What is the month with the shortest days in Onyx?

With an average of 9.8h of daylight, December has the shortest days of the year in Onyx, California.

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

In December, the average length of the day in Onyx is 9.8h.

What is the month with the least sunshine in Onyx?

January, February and December, with an average of 6.7h of sunshine, are months with the least sunshine in Onyx, California.

How long on average sun shines in December in Onyx?

In December, the average sunshine in Onyx is 6.7h.

When is the lowest UV index in Onyx?

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

What is the UV index intensity in December in Onyx?

In Onyx, California, the average daily maximum UV index in December is 2. A UV Index reading of 2, and below, represents a minimal hazard to health from unsafe exposure to the Sun's UV rays.

Average temperature in December
Onyx, CA

Average temperature in December - Onyx, CA
  • Average high temperature in December: 48.7°F

The warmest month (with the highest average high temperature) is July (85.8°F).
The month with the lowest average high temperature is December (48.7°F).

  • Average low temperature in December: 30.9°F

The month with the highest average low temperature is July (58.6°F).
The coldest month (with the lowest average low temperature) is December (30.9°F).

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Average pressure in December
Onyx, CA

Average pressure in December - Onyx, CA
  • Average pressure in December: 30.1"

The month with the highest atmospheric pressure is January (30.14").
The month with the lowest atmospheric pressure is June (29.85").

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Average wind speed in December
Onyx, CA

Average wind speed in December - Onyx, CA
  • Average wind speed in December: 5.6mph

The windiest months (with the highest average wind speed) are May and June (7.3mph).
The calmest months (with the lowest average wind speed) are January and September (5.4mph).

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Average humidity in December
Onyx, CA

Average humidity in December - Onyx, CA
  • Average humidity in December: 57%

The month with the highest relative humidity is February (59%).
The month with the lowest relative humidity is August (31%).

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Average rainfall in December
Onyx, CA

Average rainfall in December - Onyx, CA
  • Average rainfall in December: 1.89"

The wettest month (with the highest rainfall) is January (2.48").
The driest month (with the least rainfall) is June (0.08").

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Average rainfall days in December
Onyx, CA

Average rainfall days in December - Onyx, CA
  • Average rainfall days in December: 7.3 days

The month with the highest number of rainy days is March (10.3 days).
The month with the least rainy days is June (1.3 days).

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Average snowfall in December
Onyx, CA

Average snowfall in December - Onyx, CA
  • Average snowfall in December: 0.71"

The month with the highest snowfall is February (3.15").
Months with the least snowfall are May, June, July, August, September and October (0").

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Average snowfall days in December
Onyx, CA

Average snowfall days in December - Onyx, CA
  • Average snowfall days in December: 1.5 days

The month with the highest number of snowfall days is February (2.7 days).
Months with the least snowfall days are May, June, July, August, September and October (0 days).

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

Average daylight in December / Average sunshine in December - Onyx, CA
  • Average daylight in December: 9.8h

The month with the longest days is June (Average daylight: 14.6h).
The month with the shortest days is December (Average daylight: 9.8h).

  • Average sunshine in December: 6.7h

Months with the most sunshine are June and July (Average sunshine: 12.1h).
Months with the least sunshine are January, February and December (Average sunshine: 6.7).

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Average sunshine days in December
Onyx, CA

Average sunshine days in December - Onyx, CA
  • Average sunshine days in December: 22 days

The month with the most sunshine days is June (28.3 days).
The month with the least sunshine days is February (19 days).

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Average UV index in December
Onyx, CA

Average UV index in December - Onyx, CA
  • Average UV index in December: 2

Months with the highest UV index are June, July and August (UV index 6).
Months with the lowest UV index are February, November and December (UV index 2).

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Average cloud cover in December
Onyx, CA

Average cloud cover in December - Onyx, CA
  • Average cloud cover in December: 23

The month with the most cloud cover is March (Cloud cover 26).
Months with the least cloud cover are August and September (Cloud cover 5).

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Average visibility in December
Onyx, CA

Average visibility in December - Onyx, 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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