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 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
Temperature readings reach their annual highs in December, averaging 61.3°F (16.3°C) and a minimum average of 45.3°F (7.4°C).Humidity
In December, the average relative humidity is 51%.Rainfall
In Alta Loma, during December, the rain falls for 6.4 days and regularly aggregates up to 1.57" (40mm) of precipitation. In Alta Loma, during the entire year, the rain falls for 50.5 days and collects up to 7.56" (192mm) of precipitation.Daylight
With an average of 9h and 54min of daylight, December has the shortest days of the year.On the first day of the month, sunrise is at 6:38 am and sunset at 4:40 pm. On the last day of December, sunrise is at 6:55 am and sunset at 4:51 pm PST.
Sunshine
In December, the average sunshine is 7h.UV index
December is the month with the lowest UV index, with an average maximum UV index of 3. A UV Index of 3 to 5 symbolizes a medium health hazard from unprotected exposure to Sun's UV rays for ordinary individuals.Note: The maximum UV index, 3 during December, leads to the following recommendations:
Exercise caution. Those with pale skin may experience burns in less than half an hour. Direct exposure to the Sun's intense radiation around midday should be avoided for health reasons. 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
What are the coldest months?
What is the average December temperature?
What is the average humidity in December?
How many days does it rain in December?
What is the month with the shortest days?
What is the average length of the day in December?
What time are sunrise and sunset in December?
How long on average sun shines in December in Alta Loma?
When is the lowest UV index?
How high is the UV index in December?
Average temperature in December
Alta Loma, CA
- Average high temperature in December: 61.3°F
The warmest month (with the highest average high temperature) is August (91.2°F).
The month with the lowest average high temperature is December (61.3°F).
- Average low temperature in December: 45.3°F
The month with the highest average low temperature is August (66.7°F).
The coldest month (with the lowest average low temperature) is February (45.1°F).
Average pressure in December
Alta Loma, CA
- Average pressure in December: 30.07"Hg
The month with the highest atmospheric pressure is January (30.1"Hg).
The month with the lowest atmospheric pressure is June (29.86"Hg).
Average wind speed in December
Alta Loma, CA
- Average wind speed in December: 5.2mph
The windiest months (with the highest average wind speed) are April and May (5.9mph).
The calmest month (with the lowest average wind speed) is September (4.5mph).
Average humidity in December
Alta Loma, CA
- Average humidity in December: 51%
The months with the highest relative humidity are February, March and May (53%).
The month with the lowest relative humidity is August (41%).
Average rainfall in December
Alta Loma, CA
- Average rainfall in December: 1.57"
The wettest month (with the highest rainfall) is February (1.73").
The driest month (with the least rainfall) is June (0.04").
Average rainfall days in December
Alta Loma, CA
- Average rainfall days in December: 6.4 days
The month with the highest number of rainy days is March (7.5 days).
The month with the least rainy days is June (1.2 days).
Average daylight in December /
Average sunshine in December
Alta Loma, CA
- Average daylight in December: 9h and 5min
The month with the longest days is June (Average daylight: 14h and 24min).
The month with the shortest days is December (Average daylight: 9h and 54min).
- Average sunshine in December: 7h and 0min
The month with the most sunshine is July (Average sunshine: 12h and 6min).
The month with the least sunshine is February (Average sunshine: 6h and 54min).
Average sunshine days in December
Alta Loma, CA
- Average sunshine days in December: 23.2 days
The month with the most sunshine days is June (27.7 days).
The month with the least sunshine days is February (21.4 days).
Average UV index in December
Alta Loma, CA
- Average UV index in December: 3
The months with the highest UV index are July and August (UV index 7).
The month with the lowest UV index is December (UV index 3).
Average cloud cover in December
Alta Loma, CA
- Average cloud cover in December: 21
The months with the most cloud cover are March and December (Cloud cover 21).
The month with the least cloud cover is August (Cloud cover 4).
Average visibility in December
Alta Loma, 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).
Alta Loma, California, USA
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