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 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
Ontario's coldest month, December, generally records average temperatures ranging from a high of 62.1°F (16.7°C) to a low of 45.5°F (7.5°C).Humidity
In Ontario, the average relative humidity in December is 51%.Rainfall
In Ontario, in December, it is raining for 6.4 days, with typically 1.69" (43mm) of accumulated precipitation. Throughout the year, in Ontario, there are 49.6 rainfall days, and 7.8" (198mm) of precipitation is accumulated.Snowfall
January, March through December are months without snowfall.Daylight
December has the shortest days of the year, with an average of 9h and 54min of daylight.On the first day of December in Ontario, sunrise is at 6:38 am and sunset at 4:41 pm. On the last day of the month, sunrise is at 6:56 am and sunset at 4:51 pm PST.
Sunshine
February and December, with an average of 6.9h of sunshine, are months with the least sunshine.UV index
December is the month with the lowest UV index, with an average maximum UV index of 3. A UV Index estimate of 3 to 5 represents a moderate health risk from unsafe exposure to UV radiation for the ordinary person.Note: In December, the maximum UV index of 3 suggests this advice:
Ensure safety - Sun damage prevention is strongly urged. The Sun is most powerful around mid-day, so it's a good practice to reduce direct exposure. To mitigate harm from sun exposure, pick sunglasses offering UVA and UVB defense.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What month is the coldest in Ontario?
What is the usual temperature for Ontario in December?
What is the average humidity in December in Ontario?
How much does it rain in Ontario in December?
When it does not snow in Ontario?
What is the month with the shortest days in Ontario?
What is the average length of the day in December in Ontario?
What time are sunrise and sunset in December in Ontario?
What is the month with the least sunshine in Ontario?
How many hours of sunshine does Ontario have in December?
What is the month with the lowest UV index in Ontario?
How high is the UV index in December in Ontario?
Average temperature in December
Ontario, CA
- Average high temperature in December: 62.1°F
The warmest month (with the highest average high temperature) is August (91°F).
The month with the lowest average high temperature is December (62.1°F).
- Average low temperature in December: 45.5°F
The month with the highest average low temperature is August (65.8°F).
The coldest month (with the lowest average low temperature) is December (45.5°F).
Average pressure in December
Ontario, 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
Ontario, CA
- Average wind speed in December: 5.2mph
The windiest months (with the highest average wind speed) are April and May (5.8mph).
The calmest month (with the lowest average wind speed) is September (4.4mph).
Average humidity in December
Ontario, CA
- Average humidity in December: 51%
The months with the highest relative humidity are March and May (54%).
The month with the lowest relative humidity is August (42%).
Average rainfall in December
Ontario, CA
- Average rainfall in December: 1.69"
The wettest month (with the highest rainfall) is February (1.77").
The driest month (with the least rainfall) is June (0.04").
Average rainfall days in December
Ontario, CA
- Average rainfall days in December: 6.4 days
The month with the highest number of rainy days is March (7.1 days).
The month with the least rainy days is June (1.2 days).
Average snowfall days in December
Ontario, 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
Ontario, CA
- Average daylight in December: 9h and 5min
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 5min
The month with the most sunshine is July (Average sunshine: 12h and 6min).
The months with the least sunshine are February and December (Average sunshine: 6h and 54min).
Average sunshine days in December
Ontario, CA
- Average sunshine days in December: 23.2 days
The month with the most sunshine days is June (28.2 days).
The month with the least sunshine days is February (21.5 days).
Average UV index in December
Ontario, 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
Ontario, CA
- Average cloud cover in December: 21
The month with the most cloud cover is December (Cloud cover 21).
The month with the least cloud cover is August (Cloud cover 5).
Average visibility in December
Ontario, 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).
Ontario, California, USA
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