December weather forecastMountain View, CA
December
Weather in December
The first month of the winter, December, is also a moderate month in Mountain View, California, with an average temperature varying between 44.1°F (6.7°C) and 56.5°F (13.6°C).Temperature
In Mountain View, the lowest average temperatures are observed in December, with a high of 56.5°F (13.6°C) and a low of 44.1°F (6.7°C).Humidity
In Mountain View, the average relative humidity in December is 71%.Rainfall
The wettest months are February, March and December, with an average 0.83" (21mm) of rainfall.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 7:04 am and sunset at 4:50 pm. On the last day of December, in Mountain View, sunrise is at 7:22 am and sunset at 5:00 pm PST.
Sunshine
December has the least sunshine of the year, with an average of 5.9h of sunshine.UV index
The months with the lowest UV index are February, November and December, with an average maximum UV index of 3. A UV Index of 3 to 5 symbolizes a moderate health risk from unprotected exposure to Sun's UV rays for ordinary individuals.Note: The UV index of 3 during December leads to these advisories:
Stay alert. Light-skinned people could suffer burns in less than 30 minutes. When the Sun's UV radiation is most intense during midday, it's best to find shade and limit exposure. It's wise to wear UVA and UVB-blocking sunglasses when the sun shines brightly.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Mountain View, CA
- Average high temperature in December: 56.5°F
The warmest month (with the highest average high temperature) is July (79.7°F).
The month with the lowest average high temperature is December (56.5°F).
- Average low temperature in December: 44.1°F
The month with the highest average low temperature is August (56.8°F).
The coldest month (with the lowest average low temperature) is December (44.1°F).
Average pressure in December
Mountain View, CA
- Average pressure in December: 30.11"Hg
The month with the highest atmospheric pressure is January (30.13"Hg).
The months with the lowest atmospheric pressure are June and September (29.92"Hg).
Average wind speed in December
Mountain View, CA
- Average wind speed in December: 5.3mph
The windiest months (with the highest average wind speed) are April and May (6.2mph).
The calmest months (with the lowest average wind speed) are August, September, October and November (4.7mph).
Average humidity in December
Mountain View, CA
- Average humidity in December: 71%
The month with the highest relative humidity is March (73%).
The months with the lowest relative humidity are July, September and October (63%).
Average rainfall in December
Mountain View, CA
- Average rainfall in December: 0.83"
The wettest months (with the highest rainfall) are February, March and December (0.83").
The driest months (with the least rainfall) are June, July and August (0.04").
Average rainfall days in December
Mountain View, CA
- Average rainfall days in December: 8.2 days
The month with the highest number of rainy days is March (10 days).
The month with the least rainy days is August (0.4 days).
Average daylight in December /
Average sunshine in December
Mountain View, CA
- Average daylight in December: 9h and 36min
The month with the longest days is June (Average daylight: 14h and 42min).
The month with the shortest days is December (Average daylight: 9h and 36min).
- Average sunshine in December: 5h and 54min
The months with the most sunshine are July and August (Average sunshine: 12h and 0min).
The month with the least sunshine is December (Average sunshine: 5h and 54min).
Average sunshine days in December
Mountain View, CA
- Average sunshine days in December: 21.9 days
The months with the most sunshine days are July and August (29.8 days).
The month with the least sunshine days is March (19.4 days).
Average UV index in December
Mountain View, CA
- Average UV index in December: 3
The month with the highest UV index is June (UV index 6).
The months with the lowest UV index are February, November and December (UV index 3).
Average cloud cover in December
Mountain View, CA
- Average cloud cover in December: 33
The month with the most cloud cover is March (Cloud cover 35).
The month with the least cloud cover is July (Cloud cover 7).
Average visibility in December
Mountain View, 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).
