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
December is the month when Downey experiences its coldest temperatures, averaging a high of 64.9°F (18.3°C) and a low of 50.9°F (10.5°C).Humidity
In December, the average relative humidity is 54%.Rainfall
December is the month with the most rainfall. Rain falls for 5.8 days and accumulates 1.42" (36mm) of precipitation.Daylight
December has the shortest days of the year, with an average of 9h and 54min of daylight.On the first day of December in Downey, sunrise is at 6:40 am and sunset at 4:43 pm. On the last day of the month, sunrise is at 6:57 am and sunset at 4:54 pm PST.
Sunshine
The months with the least sunshine are January, February and December, with an average of 6.8h of sunshine.UV index
February, November and December, with an average maximum UV index of 4, are months with the lowest UV index. A UV Index estimate of 3 to 5 represents a medium health hazard from exposure to the Sun's UV rays for average individuals.Note: An average UV index of 4 in December transforms into this advice:
Exercise caution. The susceptibility of light skin individuals to burns is less than 30 minutes. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. 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 are the coldest months?
What is the average December temperature?
What is the average humidity in December?
What is the rainiest month?
How many days does it rain in December?
What is the month with the shortest days?
How many hours of daylight does Downey have in December?
When are sunrise and sunset in December?
What are the months with the least sunshine?
How many hours of sunshine does Downey have in December?
When is the lowest UV index?
What is the UV index reading in December?
Average temperature in December
Downey, CA
- Average high temperature in December: 64.9°F
The warmest month (with the highest average high temperature) is August (84°F).
The month with the lowest average high temperature is December (64.9°F).
- Average low temperature in December: 50.9°F
The month with the highest average low temperature is August (65.8°F).
The coldest month (with the lowest average low temperature) is February (50.5°F).
Average pressure in December
Downey, CA
- Average pressure in December: 30.07"Hg
The month with the highest atmospheric pressure is January (30.1"Hg).
The months with the lowest atmospheric pressure are June and September (29.89"Hg).
Average wind speed in December
Downey, CA
- Average wind speed in December: 5.2mph
The windiest month (with the highest average wind speed) is April (6.1mph).
The calmest months (with the lowest average wind speed) are September and October (4.7mph).
Average humidity in December
Downey, CA
- Average humidity in December: 54%
The month with the highest relative humidity is June (65%).
The month with the lowest relative humidity is November (51%).
Average rainfall in December
Downey, CA
- Average rainfall in December: 1.42"
The wettest month (with the highest rainfall) is December (1.42").
The driest month (with the least rainfall) is June (0.04").
Average rainfall days in December
Downey, CA
- Average rainfall days in December: 5.8 days
The month with the highest number of rainy days is March (6.8 days).
The month with the least rainy days is June (1.3 days).
Average daylight in December /
Average sunshine in December
Downey, 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 months with the most sunshine are July and August (Average sunshine: 12h and 0min).
The months with the least sunshine are January, February and December (Average sunshine: 6h and 48min).
Average sunshine days in December
Downey, CA
- Average sunshine days in December: 23.8 days
The month with the most sunshine days is August (26.3 days).
The month with the least sunshine days is February (22.2 days).
Average UV index in December
Downey, CA
- Average UV index in December: 4
The months with the highest UV index are June, July, August and September (UV index 6).
The months with the lowest UV index are February, November and December (UV index 4).
Average cloud cover in December
Downey, CA
- Average cloud cover in December: 22
The months with the most cloud cover are March and December (Cloud cover 22).
The month with the least cloud cover is August (Cloud cover 6).
Average visibility in December
Downey, 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).
Downey, California, USA
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