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

September 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
September, the first month of the autumn, in Ontario, is still a hot month, with temperature in the range of an average low of 62.6°F (17°C) and an average high of 89.1°F (31.7°C).

Temperature

In Ontario, California, the average high-temperature is essentially the same as in August - a still tropical 89.1°F (31.7°C). The average low-temperature, in September, is 62.6°F (17°C).

Rainfall

During September, Ontario regularly aggregates up to 0.3" (6.9mm) of precipitation. Throughout the year, in Ontario, California, 15" (382mm) of rain is accumulated.

Daylight

In Ontario, California, the average length of the day in September is 12.4h.

What is the temperature in September in Ontario?

In September, the average high-temperature is 89.1°F (31.7°C), and the average low-temperature is 62.6°F (17°C).

How much does it rain in Ontario in September?

During September, Ontario regularly aggregates up to 0.3" (6.9mm) of precipitation.

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

The average length of the day in September in Ontario is 12.4h.
Average temperature in September - Ontario, CA
  • Average high temperature in September: 89.1°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 September: 62.6°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 September - Ontario, CA
  • Average rainfall in September: 0.3"

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 September - Ontario, CA
  • Average daylight in September: 12.4h

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