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 34.5°F (1.4°C) and a low of 24.3°F (-4.3°C), December stands out as the coldest month.Humidity
In December, the average relative humidity is 81%.Rainfall
The wettest months are January and December, with an average 0.87" (22mm) of rainfall.Snowfall
Months with snowfall are January through April, September, November and December. December is the month with the most snowfall. Snow falls for 6.5 days and accumulates 3.43" (87mm) of snow.Daylight
With an average of 8h and 36min of daylight, December has the shortest days of the year.On the first day of the month, sunrise is at 7:24 am and sunset at 4:11 pm. On the last day of December, sunrise is at 7:43 am and sunset at 4:19 pm PST.
Sunshine
The average sunshine in December is 5.1h.UV index
January, February, November and December, with an average maximum UV index of 2, are months with the lowest UV index. A UV Index estimate of 2, and below, represents a minimal health hazard from unsafe exposure to UV radiation for average individuals.Note: In December, the maximum UV index of 2 translates into these guidelines:
Unlike children, who always need sun protection, most individuals can remain in the sun for up to an hour without getting burnt. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. Select sunglasses that boast both UVA and UVB protection to limit the adverse effects of the sun on the eyes. Remember to consider! The UV radiation from the Sun can be intensified nearly twice 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 is it in December?
What is the average humidity in December?
What is the rainiest month?
How much does it rain in December?
When does it snow the most?
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?
When is the sunrise / sunset in December?
How many hours of sunshine does Royal City have in December?
What is the month with the lowest UV index?
What is the UV index intensity in December?
Average temperature in December
Royal City, WA
- Average high temperature in December: 34.5°F
The warmest months (with the highest average high temperature) are July and August (88.3°F).
The month with the lowest average high temperature is December (34.5°F).
- Average low temperature in December: 24.3°F
The month with the highest average low temperature is August (61.5°F).
The coldest month (with the lowest average low temperature) is December (24.3°F).
Average pressure in December
Royal City, WA
- Average pressure in December: 30.14"Hg
The month with the highest atmospheric pressure is January (30.17"Hg).
The month with the lowest atmospheric pressure is August (29.91"Hg).
Average wind speed in December
Royal City, WA
- Average wind speed in December: 4.7mph
The windiest month (with the highest average wind speed) is April (7.6mph).
The calmest month (with the lowest average wind speed) is December (4.7mph).
Average humidity in December
Royal City, WA
- Average humidity in December: 81%
The month with the highest relative humidity is January (83%).
The month with the lowest relative humidity is July (37%).
Average rainfall in December
Royal City, WA
- Average rainfall in December: 0.87"
The wettest months (with the highest rainfall) are January and December (0.87").
The driest month (with the least rainfall) is August (0.2").
Average rainfall days in December
Royal City, WA
- Average rainfall days in December: 7.9 days
The month with the highest number of rainy days is March (10.6 days).
The month with the least rainy days is August (3.5 days).
Average snowfall in December
Royal City, WA
- Average snowfall in December: 3.43"
The month with the highest snowfall is December (3.43").
The months with the least snowfall are May, June, July, August and October (0").
Average snowfall days in December
Royal City, WA
- Average snowfall days in December: 6.5 days
The month with the highest number of snowfall days is December (6.5 days).
The months with the least snowfall days are May, June, July and August (0 days).
Average daylight in December /
Average sunshine in December
Royal City, WA
- Average daylight in December: 8h and 4min
The month with the longest days is June (Average daylight: 15h and 48min).
The month with the shortest days is December (Average daylight: 8h and 36min).
- Average sunshine in December: 5h and 1min
The months with the most sunshine are July and August (Average sunshine: 12h and 0min).
The month with the least sunshine is January (Average sunshine: 4h and 54min).
Average sunshine days in December
Royal City, WA
- Average sunshine days in December: 18.1 days
The months with the most sunshine days are July and August (25.8 days).
The month with the least sunshine days is February (16 days).
Average UV index in December
Royal City, WA
- Average UV index in December: 2
The month with the highest UV index is July (UV index 7).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in December
Royal City, WA
- Average cloud cover in December: 45
The month with the most cloud cover is January (Cloud cover 47).
The months with the least cloud cover are July and August (Cloud cover 10).
Average visibility in December
Royal City, WA
- Average visibility in December: 5mi
The months with the highest visibility are February, March, April, May, June, July, August, September, October and November (6mi).
The months with the lowest visibility are January and December (5mi).
Royal City, Washington, USA
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