December weather forecastRiverside, WA
December
Weather in December
December, the first month of the winter in Riverside, is still a freezing cold month, with temperature in the range of an average low of 18.1°F (-7.7°C) and an average high of 30.4°F (-0.9°C).Temperature
December is the coldest month, with an average high-temperature of 30.4°F (-0.9°C) and an average low-temperature of 18.1°F (-7.7°C).Humidity
In Riverside, the average relative humidity in December is 87%.Rainfall
The month with the most rainfall in Riverside is December, when the rain falls for 6.9 days and typically aggregates up to 0.94" (24mm) of precipitation.Snowfall
January through April, November and December are months with snowfall. In December, it is snowing for 8.4 days. Throughout December, 3.27" (83mm) of snow is accumulated. Throughout the year, in Riverside, there are 25.5 snowfall days, and 10.12" (257mm) of snow is accumulated.Daylight
December has the shortest days of the year, with an average of 8h and 24min of daylight.On the first day of the month, sunrise is at 7:29 am and sunset at 4:05 pm. On the last day of December, sunrise is at 7:49 am and sunset at 4:12 pm PST.
Sunshine
In December, the average sunshine in Riverside is 5h.UV index
In Riverside, the average daily maximum UV index in December is 2. A UV Index reading of 2, and below, represents a minimal health hazard from exposure to the Sun's UV radiation for the average person.Note: The maximum UV index, 2 during December, leads to the following recommendations:
Long-term sun exposure is typically not a concern for most. However, those with sensitive skin, infants, and children must always have protection. UV radiation is strongest from the Sun during midday; protect yourself by staying in shaded areas. It's wise to wear UVA and UVB-blocking sunglasses when the sun shines brightly. Take warning! The intensity of the Sun's UV radiation can be nearly amplified twice due to snow reflection.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Riverside, WA
- Average high temperature in December: 30.4°F
The warmest month (with the highest average high temperature) is July (82.6°F).
The month with the lowest average high temperature is December (30.4°F).
- Average low temperature in December: 18.1°F
The month with the highest average low temperature is August (55°F).
The coldest month (with the lowest average low temperature) is December (18.1°F).
Average pressure in December
Riverside, WA
- Average pressure in December: 30.15"Hg
The month with the highest atmospheric pressure is January (30.17"Hg).
The months with the lowest atmospheric pressure are June and August (29.93"Hg).
Average wind speed in December
Riverside, WA
- Average wind speed in December: 4.2mph
The windiest month (with the highest average wind speed) is April (5.1mph).
The calmest month (with the lowest average wind speed) is January (4mph).
Average humidity in December
Riverside, WA
- Average humidity in December: 87%
The month with the highest relative humidity is January (91%).
The months with the lowest relative humidity are July and August (42%).
Average rainfall in December
Riverside, WA
- Average rainfall in December: 0.94"
The wettest month (with the highest rainfall) is December (0.94").
The driest months (with the least rainfall) are July and August (0.2").
Average rainfall days in December
Riverside, WA
- Average rainfall days in December: 6.9 days
The month with the highest number of rainy days is March (11.5 days).
The month with the least rainy days is August (2.8 days).
Average snowfall in December
Riverside, WA
- Average snowfall in December: 3.27"
The month with the highest snowfall is January (3.39").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in December
Riverside, WA
- Average snowfall days in December: 8.4 days
The month with the highest number of snowfall days is December (8.4 days).
The months with the least snowfall days are May, June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Riverside, WA
- Average daylight in December: 8h and 24min
The month with the longest days is June (Average daylight: 16h and 6min).
The month with the shortest days is December (Average daylight: 8h and 24min).
- Average sunshine in December: 5h and 0min
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 30min).
Average sunshine days in December
Riverside, WA
- Average sunshine days in December: 17.8 days
The month with the most sunshine days is August (26.3 days).
The month with the least sunshine days is November (15.4 days).
Average UV index in December
Riverside, WA
- Average UV index in December: 2
The month with the highest UV index is July (UV index 6).
The month with the lowest UV index is November (UV index 1).
Average cloud cover in December
Riverside, WA
- 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 12).
Average visibility in December
Riverside, WA
- Average visibility in December: 4mi
The months with the highest visibility are April, May, June, July, August, September and October (6mi).
The months with the lowest visibility are January, February and December (4mi).
