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
The coldest period tends to be December, when average temperatures fluctuate between a high of 62.1°F (16.7°C) and a low of 45.5°F (7.5°C).Humidity
The average relative humidity in December is 51%.Rainfall
In December, the rain falls for 6.4 days. Throughout December, 1.69" (43mm) of precipitation is accumulated. In Upland, during the entire year, the rain falls for 49.6 days and collects up to 7.8" (198mm) of precipitation.Snowfall
In Upland, California, snow does not fall in January, March through December.Daylight
December has the shortest days of the year, with an average of 9h and 54min of daylight.On the first day of December, sunrise is at 6:38 am and sunset at 4:41 pm. On the last day of the month, sunrise is at 6:56 am and sunset at 4:51 pm PST.
Sunshine
The months with the least sunshine are February and December, with an average of 6.9h of sunshine.UV index
With an average maximum UV index of 3, December is the month with the lowest UV index. A UV Index estimate of 3 to 5 represents a medium health hazard from unprotected exposure to Sun's UV rays for ordinary individuals.Note: An average maximum UV index of 3 in December leads to these recommendations:
Undertake protective steps - Preventing sun damage is advised. To avoid the Sun's strongest rays, limit exposure around the mid-day period. To mitigate harm from sun exposure, pick sunglasses offering UVA and UVB defense.
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 in Upland?
How many days does it rain in December?
When it does not snow?
What is the month with the shortest days?
How many hours of daylight does Upland have in December?
What time are sunrise and sunset in December in Upland?
What is the month with the least sunshine?
How many hours of sunshine does Upland have in December?
What is the month with the lowest UV index?
What is the UV index intensity in December?
Average temperature in December
Upland, CA
- Average high temperature in December: 62.1°F
The warmest month (with the highest average high temperature) is August (91°F).
The month with the lowest average high temperature is December (62.1°F).
- Average low temperature in December: 45.5°F
The month with the highest average low temperature is August (65.8°F).
The coldest month (with the lowest average low temperature) is December (45.5°F).
Average pressure in December
Upland, 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
Upland, CA
- Average wind speed in December: 5.2mph
The windiest months (with the highest average wind speed) are April and May (5.8mph).
The calmest month (with the lowest average wind speed) is September (4.4mph).
Average humidity in December
Upland, CA
- Average humidity in December: 51%
The months with the highest relative humidity are March and May (54%).
The month with the lowest relative humidity is August (42%).
Average rainfall in December
Upland, CA
- Average rainfall in December: 1.69"
The wettest month (with the highest rainfall) is February (1.77").
The driest month (with the least rainfall) is June (0.04").
Average rainfall days in December
Upland, CA
- Average rainfall days in December: 6.4 days
The month with the highest number of rainy days is March (7.1 days).
The month with the least rainy days is June (1.2 days).
Average snowfall days in December
Upland, 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
Upland, 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: 6h and 5min
The month with the most sunshine is July (Average sunshine: 12h and 6min).
The months with the least sunshine are February and December (Average sunshine: 6h and 54min).
Average sunshine days in December
Upland, CA
- Average sunshine days in December: 23.2 days
The month with the most sunshine days is June (28.2 days).
The month with the least sunshine days is February (21.5 days).
Average UV index in December
Upland, 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
Upland, CA
- Average cloud cover in December: 21
The month with the most cloud cover is December (Cloud cover 21).
The month with the least cloud cover is August (Cloud cover 5).
Average visibility in December
Upland, 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).
Upland, California, USA
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