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
The coldest period is December, when temperatures fluctuate between an average high of 42.6°F (5.9°C) and a low of 36.3°F (2.4°C).Humidity
In Mount Vernon, the average relative humidity in December is 82%.Rainfall
In Mount Vernon, in December, it is raining for 19.5 days, with typically 4.06" (103mm) of accumulated precipitation. In Mount Vernon, during the entire year, the rain falls for 185.2 days and collects up to 34.72" (882mm) of precipitation.Snowfall
Months with snowfall are January through April, November and December. In December, it is snowing for 1.5 days. Throughout December, 0.47" (12mm) of snow is accumulated. In Mount Vernon, during the entire year, snow falls for 9.9 days and aggregates up to 7.91" (201mm) of snow.Daylight
The month with the shortest days is December, with an average of 8h and 24min of daylight.On the first day of December, sunrise is at 7:40 am and sunset at 4:16 pm. On the last day of the month, sunrise is at 8:00 am and sunset at 4:24 pm PST.
Sunshine
The month with the least sunshine is December, with an average of 3.9h of sunshine.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 reading of 2, and below, represents a minimal health vulnerability from unprotected exposure to Sun's UV rays for the average person.Note: In December, a daily maximum UV index of 2 leads to the following instructions:
The majority are not significantly affected by prolonged sun exposure. Infants, children, and those with fair skin must always have protection. Direct Sun exposure should be minimized especially during midday when radiation is most intense. To cut down UV radiation exposure by about half, sport a wide-brim hat. Remember this! The UV radiation of the Sun can be nearly doubled by the reflective properties of snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What part of the year is the coldest?
How cold is December?
What is the average humidity in December?
How much does it rain in Mount Vernon in December?
How much does it snow in December?
What is the month with the shortest days?
What is the average length of the day in December?
What time are sunrise and sunset in December?
What is the month with the least sunshine?
How long on average sun shines in December?
What is the month with the lowest UV index?
What is the UV index intensity in December?
Average temperature in December
Mount Vernon, WA
- Average high temperature in December: 42.6°F
The warmest months (with the highest average high temperature) are July and August (68.4°F).
The month with the lowest average high temperature is December (42.6°F).
- Average low temperature in December: 36.3°F
The month with the highest average low temperature is August (54.1°F).
The coldest month (with the lowest average low temperature) is February (36.1°F).
Average pressure in December
Mount Vernon, WA
- Average pressure in December: 30.07"Hg
The month with the highest atmospheric pressure is January (30.09"Hg).
The months with the lowest atmospheric pressure are March, August and September (30.01"Hg).
Average wind speed in December
Mount Vernon, WA
- Average wind speed in December: 7.2mph
The windiest month (with the highest average wind speed) is November (7.5mph).
The calmest month (with the lowest average wind speed) is August (3.7mph).
Average humidity in December
Mount Vernon, WA
- Average humidity in December: 82%
The months with the highest relative humidity are January and February (83%).
The month with the lowest relative humidity is July (75%).
Average rainfall in December
Mount Vernon, WA
- Average rainfall in December: 4.06"
The wettest month (with the highest rainfall) is November (4.96").
The driest month (with the least rainfall) is July (0.63").
Average rainfall days in December
Mount Vernon, WA
- Average rainfall days in December: 19.5 days
The month with the highest number of rainy days is March (20.8 days).
The month with the least rainy days is August (7.2 days).
Average snowfall in December
Mount Vernon, WA
- Average snowfall in December: 0.47"
The month with the highest snowfall is February (3.54").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in December
Mount Vernon, WA
- Average snowfall days in December: 1.5 days
The month with the highest number of snowfall days is February (3.6 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
Mount Vernon, WA
- Average daylight in December: 8h and 2min
The month with the longest days is June (Average daylight: 16h and 0min).
The month with the shortest days is December (Average daylight: 8h and 24min).
- Average sunshine in December: 3h and 5min
The months with the most sunshine are July and August (Average sunshine: 10h and 24min).
The month with the least sunshine is December (Average sunshine: 3h and 54min).
Average sunshine days in December
Mount Vernon, WA
- Average sunshine days in December: 9.9 days
The month with the most sunshine days is August (22.3 days).
The month with the least sunshine days is November (8.1 days).
Average UV index in December
Mount Vernon, 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, November and December (UV index 2).
Average cloud cover in December
Mount Vernon, WA
- Average cloud cover in December: 59
The month with the most cloud cover is December (Cloud cover 59).
The month with the least cloud cover is August (Cloud cover 26).
Average visibility in December
Mount Vernon, WA
- 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).
Mount Vernon, Washington, USA
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