December weather forecastRiverside, CA
December
Weather in December
As Riverside revels in the holiday season the weather turns chillier with December marking the onset of winter in the city. Rainfall hits a significant rise, accumulating 1.61" (41mm) through the month. Sporadic cloud cover blankets the cityscape, setting December’s distinctive ambience. Despite the characteristic chill, the city receives an average of nearly 7 hours of daily sunshine. All in all, December weather marks a characteristic close to the year with its cooler environment and soothing rainfall.Temperature
December, noted for its average high-temperature of 63.3°F (17.4°C) and an average low-temperature of 45.9°F (7.7°C), is considered the coldest month in Riverside.Humidity
In Riverside, the average relative humidity in December is 51%.Rainfall
The months with the most rainfall in Riverside, California, are February and December, with an average 1.61" (41mm) of precipitation.Snowfall
January, March through December are months without snowfall.Daylight
With an average of 9h and 54min of daylight, December has the shortest days of the year in Riverside.On the first day of the month, sunrise is at 6:37 am and sunset at 4:40 pm. On the last day of December, sunrise is at 6:54 am and sunset at 4:51 pm PST.
Sunshine
February and December, with an average of 6.8h of sunshine, are months with the least sunshine.UV index
The month with the lowest UV index in Riverside is December, with an average maximum UV index of 3. A UV Index reading of 3 to 5 represents a moderate threat to health from unprotected exposure to Sun's UV rays for average individuals.Note: The daily high UV index of 3 during December translates into the following recommendations:
Safety measures are advised. Light-skinned individuals may experience burns in under half an hour. For health reasons, it's advisable to reduce direct sun exposure during peak hours around midday. Equip yourself with UVA and UVB-filtering sunglasses on clear, sunny days.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Riverside, CA
- Average high temperature in December: 63.3°F
The warmest month (with the highest average high temperature) is August (91.2°F).
The month with the lowest average high temperature is December (63.3°F).
- Average low temperature in December: 45.9°F
The month with the highest average low temperature is August (66.4°F).
The coldest month (with the lowest average low temperature) is December (45.9°F).
Average pressure in December
Riverside, CA
- Average pressure in December: 30.07"Hg
The month with the highest atmospheric pressure is January (30.1"Hg).
The month with the lowest atmospheric pressure is June (29.86"Hg).
Average wind speed in December
Riverside, CA
- Average wind speed in December: 5mph
The windiest month (with the highest average wind speed) is May (5.6mph).
The calmest month (with the lowest average wind speed) is September (4.4mph).
Average humidity in December
Riverside, CA
- Average humidity in December: 51%
The month with the highest relative humidity is May (56%).
The month with the lowest relative humidity is August (43%).
Average rainfall in December
Riverside, CA
- Average rainfall in December: 1.61"
The wettest months (with the highest rainfall) are February and December (1.61").
The driest month (with the least rainfall) is June (0.04").
Average rainfall days in December
Riverside, CA
- Average rainfall days in December: 5.8 days
The month with the highest number of rainy days is March (7.7 days).
The month with the least rainy days is June (1.1 days).
Average snowfall days in December
Riverside, CA
- Average snowfall days in December: 0 days
The month with the highest number of snowfall days is February (0.1 days).
The months with the least snowfall days are January, March, April, May, June, July, August, September, October, November and December (0 days).
Average daylight in December /
Average sunshine in December
Riverside, CA
- Average daylight in December: 9h and 54min
The month with the longest days is June (Average daylight: 14h and 24min).
The month with the shortest days is December (Average daylight: 9h and 54min).
- Average sunshine in December: 6h and 48min
The months with the most sunshine are July and August (Average sunshine: 12h and 6min).
The months with the least sunshine are February and December (Average sunshine: 6h and 48min).
Average sunshine days in December
Riverside, CA
- Average sunshine days in December: 23.8 days
The month with the most sunshine days is June (27.9 days).
The month with the least sunshine days is February (21.6 days).
Average UV index in December
Riverside, CA
- Average UV index in December: 3
The months with the highest UV index are July and August (UV index 7).
The month with the lowest UV index is December (UV index 3).
Average cloud cover in December
Riverside, CA
- Average cloud cover in December: 22
The months with the most cloud cover are February and March (Cloud cover 23).
The month with the least cloud cover is August (Cloud cover 5).
Average visibility in December
Riverside, CA
- 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).
