December weather forecastOntario, NY
December
Weather in December
December, the first month of the winter in Ontario, is still a cold month, with an average temperature varying between 28.6°F (-1.9°C) and 36.3°F (2.4°C).Temperature
The arrival of December corresponds with a shift in temperature, down from a frosty 45.9°F (7.7°C) in November to an icy 36.3°F (2.4°C). During December, Ontario's nights hold steady with an average temperature of 28.6°F (-1.9°C), barely dropping from the daytime highs.Humidity
In Ontario, the average relative humidity in December is 81%.Rainfall
In Ontario, in December, it is raining for 10.7 days, with typically 2.68" (68mm) of accumulated precipitation. Throughout the year, there are 167.9 rainfall days, and 31.18" (792mm) of precipitation is accumulated.Snowfall
January through May, October through December are months with snowfall. In Ontario, New York, in December, during 12.8 snowfall days, 4.37" (111mm) of snow is typically accumulated. In Ontario, during the entire year, snow falls for 62.3 days and aggregates up to 20.63" (524mm) of snow.Daylight
With an average of 9h and 0min of daylight, December has the shortest days of the year in Ontario.On the first day of the month, sunrise is at 7:21 am and sunset at 4:34 pm. On the last day of December, in Ontario, sunrise is at 7:41 am and sunset at 4:43 pm EST.
Sunshine
In December, the average sunshine in Ontario is 3h.UV index
The months with the lowest UV index are January and December, with an average maximum UV index of 1. A UV Index reading of 2, and below, represents a minimal health hazard from exposure to the Sun's UV rays for the ordinary person.Note: In December, a daily UV index of 1 turns into the following recommendations:
For the majority, extended sun exposure is not of great concern. Infants and people with sensitive skin must always be protected. To avoid the Sun's strongest rays, limit exposure around the mid-day period. Sunglasses that ward off UVA and UVB rays play a pivotal role in reducing solar eye damage. Take heed! The reflection of snow can intensify the Sun's UV radiation nearly double.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Ontario, NY
- Average high temperature in December: 36.3°F
The warmest month (with the highest average high temperature) is July (76.5°F).
The month with the lowest average high temperature is January (29.7°F).
- Average low temperature in December: 28.6°F
The month with the highest average low temperature is July (64.9°F).
The coldest month (with the lowest average low temperature) is January (20.8°F).
Average pressure in December
Ontario, NY
- Average pressure in December: 30.06"Hg
The month with the highest atmospheric pressure is November (30.08"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in December
Ontario, NY
- Average wind speed in December: 12.4mph
The windiest month (with the highest average wind speed) is January (13.2mph).
The calmest month (with the lowest average wind speed) is July (7.7mph).
Average humidity in December
Ontario, NY
- Average humidity in December: 81%
The months with the highest relative humidity are January and February (83%).
The months with the lowest relative humidity are August and September (75%).
Average rainfall in December
Ontario, NY
- Average rainfall in December: 2.68"
The wettest month (with the highest rainfall) is October (3.23").
The driest month (with the least rainfall) is September (2.01").
Average rainfall days in December
Ontario, NY
- Average rainfall days in December: 10.7 days
The month with the highest number of rainy days is July (18.3 days).
The month with the least rainy days is February (7.8 days).
Average snowfall in December
Ontario, NY
- Average snowfall in December: 4.37"
The month with the highest snowfall is February (5.98").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in December
Ontario, NY
- Average snowfall days in December: 12.8 days
The month with the highest number of snowfall days is January (15.4 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Ontario, NY
- Average daylight in December: 9h and 0min
The month with the longest days is June (Average daylight: 15h and 18min).
The month with the shortest days is December (Average daylight: 9h and 0min).
- Average sunshine in December: 3h and 0min
The month with the most sunshine is July (Average sunshine: 10h and 42min).
The month with the least sunshine is January (Average sunshine: 2h and 36min).
Average sunshine days in December
Ontario, NY
- Average sunshine days in December: 8.1 days
The month with the most sunshine days is September (14.5 days).
The month with the least sunshine days is February (7.3 days).
Average UV index in December
Ontario, NY
- Average UV index in December: 1
The months with the highest UV index are July and August (UV index 6).
The months with the lowest UV index are January and December (UV index 1).
Average cloud cover in December
Ontario, NY
- Average cloud cover in December: 70
The month with the most cloud cover is January (Cloud cover 75).
The months with the least cloud cover are July and August (Cloud cover 27).
Average visibility in December
Ontario, NY
- Average visibility in December: 6mi
The months with the highest visibility are March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January and February (5mi).





