December weather forecastYountville, CA
December
Weather in December
December, the first month of the winter in Yountville, is still a cool month, with an average temperature fluctuating between 54.5°F (12.5°C) and 40.1°F (4.5°C).Temperature
With average high and low temperatures of 54.5°F (12.5°C) and 40.1°F (4.5°C) respectively, December is Yountville's coldest month.Humidity
In December, the average relative humidity is 72%.Rainfall
In December, in Yountville, the rain falls for 11.4 days. Throughout December, 2.76" (70mm) of precipitation is accumulated. In Yountville, California, during the entire year, the rain falls for 77.8 days and collects up to 16.02" (407mm) of precipitation.Daylight
December has the shortest days of the year, with an average of 9h and 30min of daylight.On the first day of the month, sunrise is at 7:08 am and sunset at 4:49 pm. On the last day of December, sunrise is at 7:26 am and sunset at 4:59 pm PST.
Sunshine
December has the least sunshine of the year, with an average of 5.6h of sunshine.UV index
January, February, November and December, with an average maximum UV index of 3, are months with the lowest UV index in Yountville. A UV Index estimate of 3 to 5 represents a moderate health risk from exposure to the Sun's UV rays for the average person.Note: The average daily UV index of 3 in December transforms into the following instructions:
Act with care - The need to guard against sun damage is communicated. It's recommended to limit sun exposure when its radiation is at its peak during midday. A wide-brimmed hat provides unparalleled sun protection for sensitive areas like the eyes, ears, and neck.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Yountville, CA
- Average high temperature in December: 54.5°F
The warmest month (with the highest average high temperature) is July (86.5°F).
The month with the lowest average high temperature is December (54.5°F).
- Average low temperature in December: 40.1°F
The month with the highest average low temperature is August (55.4°F).
The coldest month (with the lowest average low temperature) is December (40.1°F).
Average pressure in December
Yountville, CA
- Average pressure in December: 30.11"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The months with the lowest atmospheric pressure are June and August (29.91"Hg).
Average wind speed in December
Yountville, CA
- Average wind speed in December: 4.7mph
The windiest month (with the highest average wind speed) is May (6mph).
The calmest month (with the lowest average wind speed) is November (4.3mph).
Average humidity in December
Yountville, CA
- Average humidity in December: 72%
The month with the highest relative humidity is March (76%).
The month with the lowest relative humidity is September (54%).
Average rainfall in December
Yountville, CA
- Average rainfall in December: 2.76"
The wettest month (with the highest rainfall) is February (3.43").
The driest months (with the least rainfall) are July and August (0.04").
Average rainfall days in December
Yountville, CA
- Average rainfall days in December: 11.4 days
The month with the highest number of rainy days is March (13.9 days).
The month with the least rainy days is August (0.9 days).
Average daylight in December /
Average sunshine in December
Yountville, 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 36min
The month with the most sunshine is July (Average sunshine: 12h and 0min).
The month with the least sunshine is December (Average sunshine: 5h and 36min).
Average sunshine days in December
Yountville, CA
- Average sunshine days in December: 18.7 days
The month with the most sunshine days is July (29.4 days).
The month with the least sunshine days is March (15.8 days).
Average UV index in December
Yountville, 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
Yountville, CA
- Average cloud cover in December: 38
The month with the most cloud cover is March (Cloud cover 40).
The month with the least cloud cover is July (Cloud cover 6).
Average visibility in December
Yountville, 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).
