December weather forecastLos Altos, CA
December
Weather in December
The first month of the winter, December, is still a refreshing month in Los Altos, California, with an average temperature ranging between min 44.1°F (6.7°C) and max 56.5°F (13.6°C).Temperature
The coldest temperatures occur during December, when averages reach a peak of 56.5°F (13.6°C) and a low of 44.1°F (6.7°C).Humidity
In Los Altos, the average relative humidity in December is 71%.Rainfall
The wettest months in Los Altos, California, 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 December, sunrise is at 7:04 am and sunset at 4:50 pm. On the last day of the month, sunrise is at 7:22 am and sunset at 5:01 pm PST.
Sunshine
With an average of 5.9h of sunshine, December has the least sunshine of the year.UV index
The months with the lowest UV index in Los Altos are February, November and December, with an average maximum UV index of 3. A UV Index of 3 to 5 symbolizes a moderate threat to health from unsafe exposure to UV radiation for the average person.Note: An average UV index of 3 in December transforms into this advice:
Ensure safety - Sun damage prevention is strongly urged. Being exposed to the midday Sun can have harmful effects due to strong UV radiation; always take precautions. A hat with a broad brim is indispensable, filtering out up to half of UV rays.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Los Altos, 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
Los Altos, 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
Los Altos, 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
Los Altos, 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
Los Altos, 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
Los Altos, 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
Los Altos, 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
Los Altos, 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
Los Altos, 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
Los Altos, 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
Los Altos, 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).
