December weather forecastOntario, OR
December
Weather in December
The first month of the winter, December, is also a wintry month in Ontario, Oregon, with an average temperature ranging between min 23°F (-5°C) and max 36.1°F (2.3°C).Temperature
During January and December, Ontario registers its lowest temperatures, averaging a high of 36.1°F (2.3°C).Humidity
The average relative humidity in December is 78%.Rainfall
December is the month with the most rainfall. Rain falls for 8.9 days and accumulates 1.57" (40mm) of precipitation.Snowfall
Months with snowfall are January through April, November and December. The month with the most snowfall is December, when snow falls for 7.4 days and typically aggregates up to 5.35" (136mm) of snow.Daylight
December has the shortest days of the year, with an average of 9h and 0min of daylight.On the first day of December, sunrise is at 8:03 am and sunset at 5:10 pm. On the last day of the month, sunrise is at 8:22 am and sunset at 5:19 pm MST.
Sunshine
The month with the least sunshine is December, with an average of 5.1h 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 estimate of 2, and below, represents a low health risk from unsafe exposure to UV radiation for the ordinary person.Note: In December, the maximum UV index of 2 suggests these recommendations:
Most people can stay in the Sun for up to 1 hour without burning, apart from children that always must be protected from sun exposure. Solar radiation is at its peak intensity during midday, so it's advisable to stay indoors or in the shade. A hat with a broad brim is indispensable, filtering out up to half of UV rays. Heads up! The UV radiation from the Sun can almost be doubled by snow reflection.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Ontario, OR
- Average high temperature in December: 36.1°F
The warmest month (with the highest average high temperature) is July (93.2°F).
The months with the lowest average high temperature are January and December (36.1°F).
- Average low temperature in December: 23°F
The month with the highest average low temperature is July (62.2°F).
The coldest month (with the lowest average low temperature) is December (23°F).
Average pressure in December
Ontario, OR
- Average pressure in December: 30.21"Hg
The month with the highest atmospheric pressure is January (30.24"Hg).
The months with the lowest atmospheric pressure are June and August (29.92"Hg).
Average wind speed in December
Ontario, OR
- Average wind speed in December: 4.3mph
The windiest month (with the highest average wind speed) is April (6.5mph).
The calmest month (with the lowest average wind speed) is January (3.9mph).
Average humidity in December
Ontario, OR
- Average humidity in December: 78%
The month with the highest relative humidity is January (82%).
The month with the lowest relative humidity is August (29%).
Average rainfall in December
Ontario, OR
- Average rainfall in December: 1.57"
The wettest month (with the highest rainfall) is December (1.57").
The driest month (with the least rainfall) is July (0.08").
Average rainfall days in December
Ontario, OR
- Average rainfall days in December: 8.9 days
The month with the highest number of rainy days is March (13.3 days).
The month with the least rainy days is August (1.8 days).
Average snowfall in December
Ontario, OR
- Average snowfall in December: 5.35"
The month with the highest snowfall is December (5.35").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in December
Ontario, OR
- Average snowfall days in December: 7.4 days
The month with the highest number of snowfall days is December (7.4 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
Ontario, OR
- Average daylight in December: 9h and 0min
The month with the longest days is June (Average daylight: 15h and 24min).
The month with the shortest days is December (Average daylight: 9h and 0min).
- Average sunshine in December: 5h and 6min
The month with the most sunshine is July (Average sunshine: 12h and 6min).
The month with the least sunshine is December (Average sunshine: 5h and 6min).
Average sunshine days in December
Ontario, OR
- Average sunshine days in December: 17.3 days
The month with the most sunshine days is July (27.7 days).
The month with the least sunshine days is February (15.2 days).
Average UV index in December
Ontario, OR
- 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
Ontario, OR
- Average cloud cover in December: 44
The months with the most cloud cover are January and December (Cloud cover 44).
The month with the least cloud cover is July (Cloud cover 8).
Average visibility in December
Ontario, OR
- 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).
