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 lowest temperatures are recorded in December, with averages reaching a high of 37.4°F (3°C) and a low of 27°F (-2.8°C).Humidity
In Grass Valley, Oregon, the average relative humidity in December is 83%.Rainfall
In Grass Valley, during December, the rain falls for 12.6 days and regularly aggregates up to 1.73" (44mm) of precipitation. In Grass Valley, Oregon, during the entire year, the rain falls for 112.2 days and collects up to 10.91" (277mm) of precipitation.Snowfall
January through March, November and December are months with snowfall. In December, it is snowing for 3.9 days. Throughout December, 2.09" (53mm) of snow is accumulated. In Grass Valley, during the entire year, snow falls for 12.6 days and aggregates up to 7.6" (193mm) of snow.Daylight
With an average of 8h and 48min of daylight, December has the shortest days of the year.On the first day of the month, sunrise is at 7:23 am and sunset at 4:21 pm. On the last day of December, sunrise is at 7:42 am and sunset at 4:30 pm PST.
Sunshine
In December, the average sunshine in Grass Valley is 5.1h.UV index
The months with the lowest UV index in Grass Valley are January, February, November and December, with an average maximum UV index of 2. A UV Index reading of 2, and below, represents a minimal health hazard from exposure to the Sun's UV rays for average individuals.Note: In December, the maximum UV index of 2 transforms into these recommendations:
Children, babies, and those with sensitive skin should always be shielded from long periods of sun exposure. To prevent harmful UV exposure, minimize direct contact with the Sun around midday. In bright sunlight, prioritize sunglasses that grant protection from UVA and UVB radiation. Be vigilant! The reflective nature of snow can increase the Sun's UV radiation nearly twofold.
Frequently asked questions
What is the coldest month in Grass Valley?
How cold is it in Grass Valley in December?
What is the average humidity in December in Grass Valley?
How much does it rain in Grass Valley in December?
How many days does it snow in December in Grass Valley?
What is the month with the shortest days in Grass Valley?
How many hours of daylight does Grass Valley have in December?
What time are sunrise and sunset in December in Grass Valley?
How long on average sun shines in December in Grass Valley?
What is the month with the lowest UV index in Grass Valley?
How high is the UV index in December in Grass Valley?
Average temperature in December
Grass Valley, OR
- Average high temperature in December: 37.4°F
The warmest month (with the highest average high temperature) is July (83.5°F).
The month with the lowest average high temperature is December (37.4°F).
- Average low temperature in December: 27°F
The month with the highest average low temperature is August (57.9°F).
The coldest month (with the lowest average low temperature) is December (27°F).
Average pressure in December
Grass Valley, OR
- Average pressure in December: 30.14"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is August (29.95"Hg).
Average wind speed in December
Grass Valley, OR
- Average wind speed in December: 5mph
The windiest month (with the highest average wind speed) is June (7.9mph).
The calmest months (with the lowest average wind speed) are January and December (5mph).
Average humidity in December
Grass Valley, OR
- Average humidity in December: 83%
The month with the highest relative humidity is January (84%).
The month with the lowest relative humidity is August (46%).
Average rainfall in December
Grass Valley, OR
- Average rainfall in December: 1.73"
The wettest month (with the highest rainfall) is January (1.93").
The driest month (with the least rainfall) is July (0.12").
Average rainfall days in December
Grass Valley, OR
- Average rainfall days in December: 12.6 days
The month with the highest number of rainy days is March (14.3 days).
The month with the least rainy days is July (2.9 days).
Average snowfall in December
Grass Valley, OR
- Average snowfall in December: 2.09"
The month with the highest snowfall is February (2.87").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in December
Grass Valley, OR
- Average snowfall days in December: 3.9 days
The months with the highest number of snowfall days are February and December (3.9 days).
The months with the least snowfall days are April, May, June, July, August, September and October (0 days).
Average daylight in December /
Average sunshine in December
Grass Valley, OR
- Average daylight in December: 8h and 5min
The month with the longest days is June (Average daylight: 15h and 36min).
The month with the shortest days is December (Average daylight: 8h and 48min).
- 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: 5h and 0min).
Average sunshine days in December
Grass Valley, OR
- Average sunshine days in December: 13.8 days
The month with the most sunshine days is July (27 days).
The month with the least sunshine days is February (12.3 days).
Average UV index in December
Grass Valley, OR
- Average UV index in December: 2
The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in December
Grass Valley, OR
- Average cloud cover in December: 46
The month with the most cloud cover is January (Cloud cover 49).
The months with the least cloud cover are July and August (Cloud cover 9).
Average visibility in December
Grass Valley, OR
- Average visibility in December: 5mi
The months with the highest visibility are March, April, May, June, July, August, September, October and November (6mi).
The months with the lowest visibility are January, February and December (5mi).
Grass Valley, Oregon, USA
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