December weather forecastRio Vista, CA
December
Weather in December
The first month of the winter, December, is also a fresh month in Rio Vista, 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 average high and low temperatures of 55°F (12.8°C) and 41.7°F (5.4°C) respectively, December is Rio Vista's coldest month.Humidity
The average relative humidity in December is 71%.Rainfall
In Rio Vista, California, in December, during 9.7 rainfall days, 1.73" (44mm) of precipitation is typically accumulated. Throughout the year, there are 68.7 rainfall days, and 11.18" (284mm) of precipitation is accumulated.Daylight
The month with the shortest days is December, with an average of 9h and 36min of daylight.On the first day of the month, sunrise is at 7:05 am and sunset at 4:47 pm. On the last day of December, sunrise is at 7:23 am and sunset at 4:57 pm PST.
Sunshine
The month with the least sunshine is December, with an average of 5.9h of sunshine.UV index
January, February, November and December, with an average maximum UV index of 3, are months with the lowest UV index. A UV Index of 3 to 5 symbolizes a medium vulnerability from unprotected exposure to Sun's UV rays for the ordinary person.Note: The maximum UV index of 3 during December translates into these guidelines:
Ensure safety - Imperative it is to shield skin and eyes from damage. Sun's radiation is most powerful around mid-day, so it's best to limit outdoor activities during this time. 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.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Rio Vista, CA
- Average high temperature in December: 55°F
The warmest month (with the highest average high temperature) is July (91°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 (58.1°F).
The coldest month (with the lowest average low temperature) is January (41.5°F).
Average pressure in December
Rio Vista, CA
- Average pressure in December: 30.11"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed in December
Rio Vista, CA
- Average wind speed in December: 5.3mph
The windiest month (with the highest average wind speed) is June (7.6mph).
The calmest month (with the lowest average wind speed) is November (4.7mph).
Average humidity in December
Rio Vista, CA
- Average humidity in December: 71%
The months with the highest relative humidity are January and March (74%).
The month with the lowest relative humidity is September (49%).
Average rainfall in December
Rio Vista, CA
- Average rainfall in December: 1.73"
The wettest month (with the highest rainfall) is February (2.17").
The driest month (with the least rainfall) is August (0").
Average rainfall days in December
Rio Vista, CA
- Average rainfall days in December: 9.7 days
The month with the highest number of rainy days is March (13 days).
The month with the least rainy days is August (0.7 days).
Average daylight in December /
Average sunshine in December
Rio Vista, CA
- Average daylight in December: 9h and 36min
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 36min).
- Average sunshine in December: 5h and 54min
The month with the most sunshine is July (Average sunshine: 12h and 6min).
The month with the least sunshine is December (Average sunshine: 5h and 54min).
Average sunshine days in December
Rio Vista, CA
- Average sunshine days in December: 20.5 days
The month with the most sunshine days is August (29.9 days).
The month with the least sunshine days is March (17.3 days).
Average UV index in December
Rio Vista, CA
- Average UV index in December: 3
The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 3).
Average cloud cover in December
Rio Vista, CA
- Average cloud cover in December: 35
The months with the most cloud cover are March and December (Cloud cover 35).
The month with the least cloud cover is July (Cloud cover 4).
Average visibility in December
Rio Vista, 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).
