December weather forecast
California, PA

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Weather in December

December, the first month of the winter in California, is also a wintry month, with temperature in the range of an average high of 40.1°F (4.5°C) and an average low of 28.8°F (-1.8°C).

Temperature

In California, entering December brings a temperature decrement, reducing from November's frosty 49.6°F (9.8°C) to a cold 40.1°F (4.5°C). California experiences an average low-temperature reading of 28.8°F (-1.8°C) throughout December.

Humidity

The average relative humidity in December in California is 83%.

Rainfall

In California, in December, it is raining for 14 days, with typically 3.07" (78mm) of accumulated precipitation. Throughout the year, there are 191.3 rainfall days, and 35.24" (895mm) of precipitation is accumulated.

Snowfall

Months with snowfall are January through May, October through December. In December, it is snowing for 12.6 days. Throughout December, 4.88" (124mm) of snow is accumulated. Throughout the year, there are 60.2 snowfall days, and 25.08" (637mm) of snow is accumulated.

Daylight

The month with the shortest days is December, with an average of 9h and 24min of daylight.
On the first day of December in California, sunrise is at 7:23 am and sunset at 4:54 pm. On the last day of the month, sunrise is at 7:41 am and sunset at 5:04 pm EST.

Sunshine

In December, the average sunshine is 3.6h.

UV index

With an average maximum UV index of 1, December is the month with the lowest UV index. A UV Index value of 2, and less, symbolizes a minimal health vulnerability from unsafe exposure to UV radiation for average individuals.
Note: The maximum daily UV index, 1 in December, converts into the following recommendations:
Children necessitate constant protection from sunlight, unlike the majority, who can remain under the sun for about an hour without burning. Protect yourself from the midday Sun's peak UV radiation by minimizing exposure. For a sun-safe wardrobe, go for clothes that are tightly woven and generously sized. Be alert! Nearly double the UV rays from the Sun can be reflected by snow.

Frequently asked questions

How cold is December?

The average high-temperature and low-temperature during December are 40.1°F (4.5°C) and 28.8°F (-1.8°C) respectively. In August, the average heat index (a.k.a. 'feels like', 'felt air temperature'), which combines air temperature and relative humidity, is estimated at 87.8°F (31°C).

What is the average humidity in December?

The average relative humidity in December is 83%.

How many days does it rain in December?

In California, in December, during 14 rainfall days, 3.07" (78mm) of precipitation is typically accumulated.

How many days does it snow in December?

In December, it is snowing for 12.6 days. Throughout December, 4.88" (124mm) of snow is accumulated.

What is the month with the shortest days?

With an average of 9h and 24min of daylight, December has the shortest days of the year.

What is the average length of the day in December?

In California, the average day length in December is 9h and 23min.

When are sunrise and sunset in December in California?

In December, on the first day of the month, sunrise is at 7:23 am and sunset at 4:54 pm. On the last day of the month, sunrise is at 7:41 am and sunset at 5:04 pm EST.

How long on average sun shines in December?

The average sunshine duration in December is 3.6h.

What is the month with the lowest UV index?

With an average maximum UV index of 1, December is the month with the lowest UV index.

How high is the UV index in December in California?

In December, the average daily maximum UV index is 1. A UV Index reading of 2, and below, represents a low health risk from unprotected exposure to UV radiation.
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
California, PA

Average temperature in December - California, PA
  • Average high temperature in December: 40.1°F

The warmest month (with the highest average high temperature) is July (82.9°F).
The month with the lowest average high temperature is January (34°F).

  • Average low temperature in December: 28.8°F

The month with the highest average low temperature is July (61.5°F).
The coldest month (with the lowest average low temperature) is January (21.2°F).

Average pressure in December
California, PA

Average pressure in December - California, PA
  • Average pressure in December: 30.11"Hg

The month with the highest atmospheric pressure is November (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.95"Hg).

Average wind speed in December
California, PA

Average wind speed in December - California, PA
  • Average wind speed in December: 7.3mph

The windiest month (with the highest average wind speed) is January (7.9mph).
The calmest month (with the lowest average wind speed) is August (4.6mph).

Average humidity in December
California, PA

Average humidity in December - California, PA
  • Average humidity in December: 83%

The months with the highest relative humidity are January and February (84%).
The month with the lowest relative humidity is August (76%).

Average rainfall in December
California, PA

Average rainfall in December - California, PA
  • Average rainfall in December: 3.07"

The wettest month (with the highest rainfall) is May (3.78").
The driest month (with the least rainfall) is November (2.13").

Average rainfall days in December
California, PA

Average rainfall days in December - California, PA
  • Average rainfall days in December: 14 days

The month with the highest number of rainy days is May (21.8 days).
The months with the least rainy days are January and February (11.7 days).

Average snowfall in December
California, PA

Average snowfall in December - California, PA
  • Average snowfall in December: 4.88"

The month with the highest snowfall is January (6.26").
The months with the least snowfall are June, July, August and September (0").

Average snowfall days in December
California, PA

Average snowfall days in December - California, PA
  • Average snowfall days in December: 12.6 days

The month with the highest number of snowfall days is January (17.8 days).
The months with the least snowfall days are June, July, August and September (0 days).

Average daylight in December /
Average sunshine in December
California, PA

Average daylight in December / Average sunshine in December - California, PA
  • Average daylight in December: 9h and 2min

The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 24min).

  • Average sunshine in December: 3h and 4min

The month with the most sunshine is August (Average sunshine: 10h and 12min).
The month with the least sunshine is January (Average sunshine: 3h and 0min).

Average sunshine days in December
California, PA

Average sunshine days in December - California, PA
  • Average sunshine days in December: 9.9 days

The month with the most sunshine days is November (14.3 days).
The month with the least sunshine days is January (6.8 days).

Average UV index in December
California, PA

Average UV index in December - California, PA
  • Average UV index in December: 1

The months with the highest UV index are May, June and July (UV index 6).
The month with the lowest UV index is December (UV index 1).

Average cloud cover in December
California, PA

Average cloud cover in December - California, PA
  • Average cloud cover in December: 64

The month with the most cloud cover is January (Cloud cover 68).
The month with the least cloud cover is August (Cloud cover 33).

Average visibility in December
California, PA

Average visibility in December - California, PA
  • Average visibility in December: 5mi

The months with the highest visibility are April, August and November (6mi).
The months with the lowest visibility are January and February (4mi).

California, Pennsylvania, USA

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