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
With average high temperatures of 55.6°F (13.1°C) and lows of 41.9°F (5.5°C), December is the coldest month.Humidity
In December, the average relative humidity in Riverdale Park is 70%.Rainfall
In Riverdale Park, during December, the rain falls for 8.2 days and regularly aggregates up to 1.22" (31mm) of precipitation. Throughout the year, there are 54.3 rainfall days, and 6.54" (166mm) of precipitation is accumulated.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 7:01 am and sunset at 4:45 pm. On the last day of December, sunrise is at 7:18 am and sunset at 4:56 pm PST.
Sunshine
December has the least sunshine of the year, with an average of 6h of sunshine.UV index
January, February, November and December, with an average maximum UV index of 3, are months with the lowest UV index. A UV Index of 3 to 5 symbolizes a medium vulnerability from exposure to the Sun's UV radiation for ordinary individuals.Note: The maximum UV index of 3 during December translates into these guidelines:
Undertake precautions - Obligation exists to protect against skin and eye damage. Avoiding direct sun during mid-day hours can prevent harmful UV radiation exposure. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What time of the year is the coldest?
What is the average December temperature?
What is the average humidity in December?
How much does it rain in December?
What is the month with the shortest days?
How many hours of daylight does Riverdale Park have in December?
When is the sunrise / sunset in December?
What is the month with the least sunshine?
How many hours of sunshine does Riverdale Park have in December?
When is the lowest UV index?
What is the UV index reading in December?
Average temperature in December
Riverdale Park, CA
- Average high temperature in December: 55.6°F
The warmest month (with the highest average high temperature) is July (97.7°F).
The month with the lowest average high temperature is December (55.6°F).
- Average low temperature in December: 41.9°F
The month with the highest average low temperature is July (62.1°F).
The coldest months (with the lowest average low temperature) are January and December (41.9°F).
Average pressure in December
Riverdale Park, CA
- Average pressure in December: 30.12"Hg
The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed in December
Riverdale Park, CA
- Average wind speed in December: 5.7mph
The windiest month (with the highest average wind speed) is June (7.3mph).
The calmest month (with the lowest average wind speed) is November (5.2mph).
Average humidity in December
Riverdale Park, CA
- Average humidity in December: 70%
The month with the highest relative humidity is January (72%).
The month with the lowest relative humidity is July (37%).
Average rainfall in December
Riverdale Park, CA
- Average rainfall in December: 1.22"
The wettest month (with the highest rainfall) is March (1.3").
The driest months (with the least rainfall) are July and August (0.04").
Average rainfall days in December
Riverdale Park, CA
- Average rainfall days in December: 8.2 days
The month with the highest number of rainy days is March (10.3 days).
The month with the least rainy days is August (0.9 days).
Average daylight in December /
Average sunshine in December
Riverdale Park, CA
- Average daylight in December: 9h and 4min
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: 6h and 0min
The month with the most sunshine is July (Average sunshine: 12h and 6min).
The month with the least sunshine is December (Average sunshine: 6h and 0min).
Average sunshine days in December
Riverdale Park, CA
- Average sunshine days in December: 22 days
The month with the most sunshine days is August (29.2 days).
The month with the least sunshine days is March (19.6 days).
Average UV index in December
Riverdale Park, CA
- Average UV index in December: 3
The months with the highest UV index are June, July and August (UV index 7).
The months with the lowest UV index are January, February, November and December (UV index 3).
Average cloud cover in December
Riverdale Park, CA
- Average cloud cover in December: 32
The month with the most cloud cover is March (Cloud cover 33).
The month with the least cloud cover is July (Cloud cover 4).
Average visibility in December
Riverdale Park, 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).
Riverdale Park, California, USA
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