Contents
- Weather in December
- Frequently asked questions
- Average temperature in December
- Average pressure in December
- Average wind speed in December
- Average humidity in December
- Average rainfall in December
- Average rainfall days in December
- Average snowfall days in December
- Average daylight in December
- Average sunshine in December
- Average sunshine days in December
- Average UV index in December
- Average cloud cover in December
- Average visibility in December
Weather in December
Temperature
In Island Mountain, the month of December is known for its lowest average temperatures, reaching a high of 53.4°F (11.9°C) and a low of 43.9°F (6.6°C).Humidity
In December, the average relative humidity is 78%.Rainfall
December is the month with the most rainfall. Rain falls for 14.8 days and accumulates 5.31" (135mm) of precipitation.Snowfall
January, March through December are months without snowfall.Daylight
With an average of 9h and 24min of daylight, December has the shortest days of the year.On the first day of December, sunrise is at 7:17 am and sunset at 4:49 pm. On the last day of the month, sunrise is at 7:35 am and sunset at 4:59 pm PST.
Sunshine
With an average of 5h of sunshine, December has the least sunshine of the year.UV index
January through March, November and December, with an average maximum UV index of 3, are months with the lowest UV index. A UV Index reading of 3 to 5 represents a medium health hazard from unprotected exposure to Sun's UV rays for average individuals.Note: In December, the maximum UV index of 3 translates into these guidelines:
Prioritize safety - Recommendations to avert sunburn are shared. Considering the harmful UV rays from the Sun during midday, it's essential to reduce exposure. To cut down UV radiation exposure by about half, sport a wide-brim hat.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the coldest month?
What is the average December temperature?
What is the average humidity in December in Island Mountain?
What is the rainiest month in Island Mountain?
How much does it rain in December?
When it does not snow?
What is the month with the shortest days?
How many hours of daylight does Island Mountain have in December?
What time are sunrise and sunset in December?
What is the month with the least sunshine?
How long on average sun shines in December?
What are the months with the lowest UV index?
What is the UV index intensity in December?
Average temperature in December
Island Mountain, CA
- Average high temperature in December: 53.4°F
The warmest month (with the highest average high temperature) is September (69.8°F).
The month with the lowest average high temperature is December (53.4°F).
- Average low temperature in December: 43.9°F
The months with the highest average low temperature are July, August and September (54.3°F).
The coldest month (with the lowest average low temperature) is February (43.5°F).
Average pressure in December
Island Mountain, CA
- Average pressure in December: 30.1"Hg
The month with the highest atmospheric pressure is January (30.13"Hg).
The months with the lowest atmospheric pressure are August and September (29.95"Hg).
Average wind speed in December
Island Mountain, CA
- Average wind speed in December: 8.6mph
The windiest month (with the highest average wind speed) is June (10.6mph).
The calmest months (with the lowest average wind speed) are January and August (7.8mph).
Average humidity in December
Island Mountain, CA
- Average humidity in December: 78%
The month with the highest relative humidity is March (81%).
The month with the lowest relative humidity is September (72%).
Average rainfall in December
Island Mountain, CA
- Average rainfall in December: 5.31"
The wettest month (with the highest rainfall) is December (5.31").
The driest month (with the least rainfall) is July (0.08").
Average rainfall days in December
Island Mountain, CA
- Average rainfall days in December: 14.8 days
The month with the highest number of rainy days is March (16.4 days).
The month with the least rainy days is August (1.8 days).
Average snowfall days in December
Island Mountain, CA
- Average snowfall days in December: 0 days
The month with the highest number of snowfall days is February (0.1 days).
The months with the least snowfall days are January, March, April, May, June, July, August, September, October, November and December (0 days).
Average daylight in December /
Average sunshine in December
Island Mountain, CA
- Average daylight in December: 9h and 2min
The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 24min).
- Average sunshine in December: 5h and 0min
The months with the most sunshine are July and August (Average sunshine: 11h and 42min).
The month with the least sunshine is December (Average sunshine: 5h and 0min).
Average sunshine days in December
Island Mountain, CA
- Average sunshine days in December: 15.5 days
The month with the most sunshine days is July (28.4 days).
The month with the least sunshine days is March (13.1 days).
Average UV index in December
Island Mountain, CA
- Average UV index in December: 3
The months with the highest UV index are June, July and August (UV index 5).
The months with the lowest UV index are January, February, March, November and December (UV index 3).
Average cloud cover in December
Island Mountain, CA
- Average cloud cover in December: 44
The month with the most cloud cover is March (Cloud cover 46).
The month with the least cloud cover is July (Cloud cover 10).
Average visibility in December
Island Mountain, 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).
Island Mountain, California, USA
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