December weather forecastPenryn, CA
December
Weather in December
December, the first month of the winter in Penryn, is also a fresh month, with an average temperature ranging between min 39.2°F (4°C) and max 53.4°F (11.9°C).Temperature
December tends to be the coldest month, with temperatures averaging a daily high of 53.4°F (11.9°C) and a low of 39.2°F (4°C).Humidity
In December, the average relative humidity in Penryn, California, is 68%.Rainfall
In December, the rain falls for 11.5 days. Throughout December, 4.69" (119mm) of precipitation is accumulated. Throughout the year, there are 84.8 rainfall days, and 28.86" (733mm) of precipitation is accumulated.Snowfall
February, March and December are months with snowfall. December is the first month it typically snows. Throughout December, in the average 0.3 snowfall days, it receives 0.63" (16mm) of snow. In Penryn, California, during the entire year, snow falls for 1.2 days and aggregates up to 2.09" (53mm) of snow.Daylight
With an average of 9h and 30min of daylight, December has the shortest days of the year.On the first day of the month, sunrise is at 7:04 am and sunset at 4:43 pm. On the last day of December, sunrise is at 7:23 am and sunset at 4:53 pm PST.
Sunshine
The months with the least sunshine are January and December, with an average of 5.8h of sunshine.UV index
The months with the lowest UV index are January, February, November and December, with an average maximum UV index of 3. A UV Index reading of 3 to 5 represents a medium health hazard from unprotected exposure to Sun's UV rays for the ordinary person.Note: A daily high UV index of 3 in December leads to these guidelines:
Ensure safety - Imperative it is to shield skin and eyes from damage. Limiting sun exposure during midday hours helps in reducing the harmful effects of UV radiation. On days when the sun blazes, arm yourself with sunglasses that block UVA and UVB radiation. Consider this! The reflection from snow can almost double the intensity of the Sun's UV radiation.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Penryn, CA
- Average high temperature in December: 53.4°F
The warmest month (with the highest average high temperature) is July (91.9°F).
The month with the lowest average high temperature is December (53.4°F).
- Average low temperature in December: 39.2°F
The month with the highest average low temperature is July (60.6°F).
The coldest month (with the lowest average low temperature) is December (39.2°F).
Average pressure in December
Penryn, CA
- Average pressure in December: 30.13"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.9"Hg).
Average wind speed in December
Penryn, CA
- Average wind speed in December: 4.9mph
The windiest months (with the highest average wind speed) are February and March (5.7mph).
The calmest month (with the lowest average wind speed) is August (4.3mph).
Average humidity in December
Penryn, 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 (38%).
Average rainfall in December
Penryn, CA
- Average rainfall in December: 4.69"
The wettest month (with the highest rainfall) is March (5.63").
The driest months (with the least rainfall) are July and August (0.04").
Average rainfall days in December
Penryn, CA
- Average rainfall days in December: 11.5 days
The month with the highest number of rainy days is March (15.4 days).
The month with the least rainy days is July (1 days).
Average snowfall in December
Penryn, CA
- Average snowfall in December: 0.63"
The month with the highest snowfall is February (1.18").
The months with the least snowfall are January, April, May, June, July, August, September, October and November (0").
Average snowfall days in December
Penryn, CA
- Average snowfall days in December: 0.3 days
The month with the highest number of snowfall days is February (0.6 days).
The months with the least snowfall days are January, April, May, June, July, August, September, October and November (0 days).
Average daylight in December /
Average sunshine in December
Penryn, CA
- Average daylight in December: 9h and 30min
The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 30min).
- Average sunshine in December: 5h and 48min
The month with the most sunshine is July (Average sunshine: 12h and 6min).
The months with the least sunshine are January and December (Average sunshine: 5h and 48min).
Average sunshine days in December
Penryn, CA
- Average sunshine days in December: 18.7 days
The month with the most sunshine days is July (29.6 days).
The month with the least sunshine days is March (14.6 days).
Average UV index in December
Penryn, CA
- Average UV index in December: 3
The months with the highest UV index are June and July (UV index 7).
The months with the lowest UV index are January, February, November and December (UV index 3).
Average cloud cover in December
Penryn, CA
- Average cloud cover in December: 34
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
Penryn, 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).
