Ontario
California, USA
Long-term weather forecast
Long-term weather forecast

December weather forecast and climate
Ontario, CA

A clear street near the luxurious residential estate in Ontario, California, with a scenic background of a hilly landscape, the clear blue sky
A clear street near the luxurious residential estate in Ontario, California, with a scenic background of a hilly landscape, the clear blue sky
The first month of the winter, December, is still a comfortable month in Ontario, California, with temperature in the range of an average low of 42.6°F (5.9°C) and an average high of 65.7°F (18.7°C).

Temperature

In Ontario, the average high-temperature slightly decreases, from an agreeable 72.7°F (22.6°C) in November, to an enjoyable 65.7°F (18.7°C). In December, in Ontario, California, the average low-temperature is 42.6°F (5.9°C).

Rainfall

Throughout December, 2.3" (58.9mm) of precipitation is accumulated. Throughout the year, in Ontario, 15" (382mm) of rain is accumulated.

Daylight

With an average of 9.9h of daylight, December has the shortest days of the year.

What is the temperature in December in Ontario?

In December, in Ontario, the average high-temperature is 65.7°F (18.7°C), and the average low-temperature is 42.6°F (5.9°C).

How much does it rain in Ontario in December?

In Ontario, in December, 2.3" (58.9mm) of precipitation is typically accumulated.

What is the month with the shortest days in Ontario?

With an average of 9.9h of daylight, December has the shortest days of the year in Ontario, California.

What is the average length of the day in December in Ontario?

The average length of the day in December in Ontario is 9.9h.
Average temperature in December - Ontario, CA
  • Average high temperature in December: 65.6°F

The warmest month (with the highest average high temperature) is August (93.6°F).
The month with the lowest average high temperature is January (65.2°F).

  • Average low temperature in December: 42.7°F

The month with the highest average low temperature is August (64.7°F).
The coldest month (with the lowest average low temperature) is December (42.7°F).

Average rainfall in December - Ontario, CA
  • Average rainfall in December: 2.3"

The wettest month (with the highest rainfall) is February (3.4").
Driest months (with the lowest rainfall) are June, July and August (0.1").

Average daylight in December - Ontario, CA
  • Average daylight in December: 9.9h

The month with the longest days is June (Average daylight: 14.4h).
The month with shortest days is December (Average daylight: 9.9h).