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 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
With average temperatures fluctuating between a high of 41.4°F (5.2°C) and a low of 32°F (0°C), December stands out as the coldest month.Humidity
The average relative humidity in December is 86%.Rainfall
December is the month with the most rainfall. Rain falls for 19.3 days and accumulates 5.35" (136mm) of precipitation.Snowfall
Months with snowfall are January through April, November and December. In December, it is snowing for 2.9 days. Throughout December, 1.26" (32mm) of snow is accumulated. In Sumner, during the entire year, snow falls for 15.8 days and aggregates up to 9.09" (231mm) of snow.Daylight
The month with the shortest days is December, with an average of 8h and 36min of daylight.On the first day of the month, sunrise is at 7:35 am and sunset at 4:20 pm. On the last day of December, sunrise is at 7:55 am and sunset at 4:29 pm PST.
Sunshine
With an average of 4.2h of sunshine, December has the least sunshine of the year in Sumner.UV index
The months with the lowest UV index are January, February, October through December, with an average maximum UV index of 2. A UV Index of 2, and less, symbolizes a minimal health vulnerability from unprotected exposure to Sun's UV rays for average individuals.Note: A maximum high UV index of 2 in December translates into the following recommendations:
Those with sensitive skin, infants, and children require constant safeguarding from prolonged sun exposure. To avoid the Sun's strongest rays, limit exposure around the mid-day period. Sunglasses that guard against UVA and UVB rays are pivotal in minimizing sun-induced ocular damage. Remember! The Sun's UV radiation can be magnified almost twofold by the reflection of snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are the coldest months?
How cold does it get in Sumner in December?
What is the average humidity in December?
What is the wettest month?
How many days does it rain in December?
How many days does it snow in December?
What is the month with the shortest days?
What is the average length of the day in December in Sumner?
When is the sunrise / sunset in December?
What is the month with the least sunshine?
How many hours of sunshine does Sumner have in December?
When is the lowest UV index?
What is the UV index reading in December?
Average temperature in December
Sumner, WA
- Average high temperature in December: 41.4°F
The warmest month (with the highest average high temperature) is August (75.7°F).
The month with the lowest average high temperature is December (41.4°F).
- Average low temperature in December: 32°F
The month with the highest average low temperature is August (50.9°F).
The coldest month (with the lowest average low temperature) is December (32°F).
Average pressure in December
Sumner, WA
- Average pressure in December: 30.09"Hg
The month with the highest atmospheric pressure is January (30.1"Hg).
The month with the lowest atmospheric pressure is August (30"Hg).
Average wind speed in December
Sumner, WA
- Average wind speed in December: 4.5mph
The windiest month (with the highest average wind speed) is January (4.9mph).
The calmest month (with the lowest average wind speed) is August (3.5mph).
Average humidity in December
Sumner, WA
- Average humidity in December: 86%
The month with the highest relative humidity is January (87%).
The months with the lowest relative humidity are July and August (70%).
Average rainfall in December
Sumner, WA
- Average rainfall in December: 5.35"
The wettest month (with the highest rainfall) is December (5.35").
The driest month (with the least rainfall) is July (0.51").
Average rainfall days in December
Sumner, WA
- Average rainfall days in December: 19.3 days
The month with the highest number of rainy days is March (20.7 days).
The month with the least rainy days is August (6.8 days).
Average snowfall in December
Sumner, WA
- Average snowfall in December: 1.26"
The month with the highest snowfall is February (3.31").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in December
Sumner, WA
- Average snowfall days in December: 2.9 days
The month with the highest number of snowfall days is February (5.3 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).
Average daylight in December /
Average sunshine in December
Sumner, WA
- Average daylight in December: 8h and 4min
The month with the longest days is June (Average daylight: 15h and 54min).
The month with the shortest days is December (Average daylight: 8h and 36min).
- Average sunshine in December: 4h and 1min
The month with the most sunshine is August (Average sunshine: 10h and 54min).
The month with the least sunshine is December (Average sunshine: 4h and 12min).
Average sunshine days in December
Sumner, WA
- Average sunshine days in December: 10.1 days
The month with the most sunshine days is August (22 days).
The month with the least sunshine days is February (8.2 days).
Average UV index in December
Sumner, WA
- Average UV index in December: 2
The month with the highest UV index is July (UV index 5).
The months with the lowest UV index are January, February, October, November and December (UV index 2).
Average cloud cover in December
Sumner, WA
- Average cloud cover in December: 56
The months with the most cloud cover are January and December (Cloud cover 56).
The month with the least cloud cover is August (Cloud cover 25).
Average visibility in December
Sumner, WA
- Average visibility in December: 4mi
The months with the highest visibility are July and August (6mi).
The months with the lowest visibility are January, February and December (4mi).
Sumner, Washington, USA
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