December weather forecast
Penn Valley, CA

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Weather in December

The first month of the winter, December, is also a fresh month in Penn Valley, California, with an average temperature varying between 51.3°F (10.7°C) and 37.2°F (2.9°C).

Temperature

In Penn Valley, the lowest temperatures are generally noted in December, averaging a high of 51.3°F (10.7°C) and a low of 37.2°F (2.9°C).

Humidity

In December, the average relative humidity is 68%.

Rainfall

In Penn Valley, in December, during 10.7 rainfall days, 5.35" (136mm) of precipitation is typically accumulated. In Penn Valley, during the entire year, the rain falls for 82 days and collects up to 33.11" (841mm) of precipitation.

Snowfall

January through May, November and December are months with snowfall. In Penn Valley, California, during December, snow falls for 0.5 days and regularly aggregates up to 0.71" (18mm) of snow. Throughout the year, in Penn Valley, there are 6.8 snowfall days, and 14.41" (366mm) of snow is accumulated.

Daylight

The month with the shortest days is December, with an average of 9h and 30min of daylight.
On the first day of December in Penn Valley, sunrise is at 7:05 am and sunset at 4:42 pm. On the last day of the month, sunrise is at 7:24 am and sunset at 4:52 pm PST.

Sunshine

In Penn Valley, the average sunshine in December is 5.8h.

UV index

In December, the average daily maximum UV index is 3. A UV Index value of 3 to 5 symbolizes a moderate health risk from exposure to the Sun's UV rays for the ordinary person.
Note: The UV index of 3 during December leads to these advisories:
Ensure safety - Recommendations to avert sunburn are presented. UV radiation is strongest from the Sun during midday; protect yourself by staying in shaded areas. Sunglasses providing both UVA and UVB protection are non-negotiable on sunlit days. Forewarned is forearmed! The Sun's UV radiation can be almost doubled in intensity by snow reflection.
Updated: Jun 23, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the coldest month?

Penn Valley notes the coldest temperatures in December, with a average high of 51.3°F (10.7°C) and a low of 37.2°F (2.9°C).

What is the average December temperature?

In Penn Valley, in December, the average high-temperature is 51.3°F (10.7°C), and the average low-temperature is 37.2°F (2.9°C). The average heat index (a.k.a. 'real feel', 'apparent temperature'), which combines relative humidity and air temperature, in September is calculated to be 82.4°F (28°C).

What is the average humidity in December?

In Penn Valley, the average relative humidity in December is 68%.

How many days does it rain in December?

In December, in Penn Valley, the rain falls for 10.7 days. Throughout December, 5.35" (136mm) of precipitation is accumulated.

How many days does it snow in December?

In Penn Valley, in December, snow falls for 0.5 days, with typically accumulated 0.71" (18mm) of snow.

What is the month with the shortest days?

With an average of 9h and 30min of daylight, December has the shortest days of the year.

What is the average length of the day in December?

In Penn Valley, the average day length in December is 9h and 28min.

When is the sunrise / sunset in December?

On the first day of December, sunrise is at 7:05 am and sunset at 4:42 pm. On the last day of the month, sunrise is at 7:24 am and sunset at 4:52 pm PST.

How long on average sun shines in December?

In Penn Valley, the average sunshine duration in December is 5.8h.

What is the UV index intensity in December?

In December, the average daily maximum UV index in Penn Valley is 3. A UV Index value 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
Penn Valley, CA

Average temperature in December - Penn Valley, CA
  • Average high temperature in December: 51.3°F

The warmest month (with the highest average high temperature) is July (90.1°F).
The month with the lowest average high temperature is December (51.3°F).

  • Average low temperature in December: 37.2°F

The month with the highest average low temperature is July (60.1°F).
The coldest month (with the lowest average low temperature) is December (37.2°F).

Average pressure in December
Penn Valley, CA

Average pressure in December - Penn Valley, CA
  • Average pressure in December: 30.14"Hg

The month with the highest atmospheric pressure is January (30.17"Hg).
The month with the lowest atmospheric pressure is June (29.9"Hg).

Average wind speed in December
Penn Valley, CA

Average wind speed in December - Penn Valley, CA
  • Average wind speed in December: 5.3mph

The windiest month (with the highest average wind speed) is February (6mph).
The calmest month (with the lowest average wind speed) is August (4.8mph).

Average humidity in December
Penn Valley, CA

Average humidity in December - Penn Valley, CA
  • Average humidity in December: 68%

The month with the highest relative humidity is March (75%).
The month with the lowest relative humidity is July (37%).

Average rainfall in December
Penn Valley, CA

Average rainfall in December - Penn Valley, CA
  • Average rainfall in December: 5.35"

The wettest month (with the highest rainfall) is March (6.57").
The driest months (with the least rainfall) are July and August (0.04").

Average rainfall days in December
Penn Valley, CA

Average rainfall days in December - Penn Valley, CA
  • Average rainfall days in December: 10.7 days

The month with the highest number of rainy days is March (15.1 days).
The month with the least rainy days is July (1.1 days).

Average snowfall in December
Penn Valley, CA

Average snowfall in December - Penn Valley, CA
  • Average snowfall in December: 0.71"

The month with the highest snowfall is February (6.42").
The months with the least snowfall are June, July, August, September and October (0").

Average snowfall days in December
Penn Valley, CA

Average snowfall days in December - Penn Valley, CA
  • Average snowfall days in December: 0.5 days

The month with the highest number of snowfall days is March (2.4 days).
The months with the least snowfall days are June, July, August, September and October (0 days).

Average daylight in December /
Average sunshine in December
Penn Valley, CA

Average daylight in December / Average sunshine in December - Penn Valley, CA
  • Average daylight in December: 9h and 3min

The month with the longest days is June (Average daylight: 14h and 54min).
The month with the shortest days is December (Average daylight: 9h and 30min).

  • Average sunshine in December: 5h and 5min

The month with the most sunshine is July (Average sunshine: 12h and 12min).
The month with the least sunshine is January (Average sunshine: 5h and 42min).

Average sunshine days in December
Penn Valley, CA

Average sunshine days in December - Penn Valley, CA
  • Average sunshine days in December: 19.1 days

The month with the most sunshine days is July (29.8 days).
The month with the least sunshine days is March (14.8 days).

Average UV index in December
Penn Valley, CA

Average UV index in December - Penn Valley, CA
  • Average UV index in December: 3

The month with the highest UV index is July (UV index 7).
The month with the lowest UV index is November (UV index 2).

Average cloud cover in December
Penn Valley, CA

Average cloud cover in December - Penn Valley, CA
  • Average cloud cover in December: 35

The month with the most cloud cover is March (Cloud cover 41).
The month with the least cloud cover is July (Cloud cover 4).

Average visibility in December
Penn Valley, CA

Average visibility in December - Penn Valley, 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).

Penn Valley, California, USA

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