Monthly weather forecast and climate
Ontario, CA

The luxurious residential estate in Ontario, California, with a scenic background of a hilly landscape
The luxurious residential estate in Ontario, California, with a scenic background of a hilly landscape

Weather in January

January, like December, in Ontario, California, is another comfortable winter month, with average temperature fluctuating between 46.8°F (8.2°C) and 64.6°F (18.1°C). In January, the average high-temperature is almost the same as in December - a still enjoyable 64.6°F (18.1°C). Weather in January »

Weather in February

February, the last month of the winter, in Ontario, is also an enjoyable month, with average temperature ranging between min 45.7°F (7.6°C) and max 64°F (17.8°C). In February, the average high-temperature is almost the same as in January - a still enjoyable 64°F (17.8°C). Weather in February »

Weather in March

March, the first month of the spring, in Ontario, is a pleasant month, with average temperature fluctuating between 68.4°F (20.2°C) and 46.9°F (8.3°C). In March, the average high-temperature is almost the same as in February - an agreeable 68.4°F (20.2°C). Weather in March »

Weather in April

April, like March, is an agreeable spring month in Ontario, California, with average temperature fluctuating between 50.2°F (10.1°C) and 72.9°F (22.7°C). In April, the average high-temperature is relatively the same as in March - a still pleasant 72.9°F (22.7°C). Weather in April »

Weather in May

The last month of the spring, May, is a warm month in Ontario, California, with average temperature varying between 53.6°F (12°C) and 76.6°F (24.8°C). In Ontario, the average high-temperature in May is essentially the same as in April - a moderately hot 76.6°F (24.8°C). Weather in May »

Weather in June

The first month of the summer, June, is still a warm month in Ontario, California, with average temperature varying between 84°F (28.9°C) and 58.5°F (14.7°C). In June, the average high-temperature marginally rises, from a warm 76.6°F (24.8°C) in May, to a still moderately hot 84°F (28.9°C). Weather in June »

Weather in July

July in Ontario, California, is a hot summer month, with average temperature varying between 90°F (32.2°C) and 64.8°F (18.2°C). In Ontario, the average high-temperature in July slightly increases, from a moderately hot 84°F (28.9°C) in June, to a hot 90°F (32.2°C). Weather in July »

Weather in August

August, the last month of the summer, in Ontario, is also a hot month, with average temperature ranging between max 91°F (32.8°C) and min 65.8°F (18.8°C). August is the warmest month, with an average high-temperature of 91°F (32.8°C) and an average low-temperature of 65.8°F (18.8°C). In August, the average heat index is calculated to a hot 93°F (33.9°C). Weather in August »

Weather in September

The first month of the autumn, September, is still a tropical month in Ontario, California, with average temperature varying between 63.5°F (17.5°C) and 88.2°F (31.2°C). In Ontario, the average high-temperature is essentially the same as in August - a still tropical 88.2°F (31.2°C). Weather in September »

Weather in October

October, like September, in Ontario, California, is another warm autumn month, with temperature in the range of an average high of 79°F (26.1°C) and an average low of 57.9°F (14.4°C). In Ontario, California, the average high-temperature decreases, from a hot 88.2°F (31.2°C) in September, to a warm 79°F (26.1°C). Weather in October »

Weather in November

The last month of the autumn, November, is another pleasant month in Ontario, California, with average temperature fluctuating between 70.7°F (21.5°C) and 50.9°F (10.5°C). In Ontario, the average high-temperature in November marginally drops, from a warm 79°F (26.1°C) in October, to an agreeable 70.7°F (21.5°C). Weather in November »

Weather in December

The first month of the winter, December, is also an enjoyable month in Ontario, California, with average temperature varying between 45.5°F (7.5°C) and 62.1°F (16.7°C). December is the coldest month, with an average high-temperature of 62.1°F (16.7°C) and an average low-temperature of 45.5°F (7.5°C). Weather in December »
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FAQ

How much does it rain in Ontario?

Throughout the year, in Ontario, California, there are 49.6 rainfall days, and 7.8" (198mm) of precipitation is accumulated.

How many days does it snow in Ontario?

In Ontario, California, during the entire year, snow falls for 0.1 days.

When it does not snow in Ontario?

January, March through December are months without snowfall.

What is the wettest month in Ontario?

The month with the most rainfall in Ontario, California, is February when the rain falls for 6 days and typically aggregates up to 1.77" (45mm) of precipitation.

When does it snow in Ontario?

February is the only month when snow falls in Ontario, California.

When does it snow the most in Ontario?

February has the most snowfall days of the year in Ontario, California. Snow falls for 0.1 days.

What is the month with the least sunshine in Ontario?

Months with the least sunshine in Ontario, California, are February and December, with an average of 6.9h of sunshine.

What are the most humid months in Ontario?

Months with the highest humidity in Ontario are March and May, with an average relative humidity of 54%.

What is the driest month in Ontario?

The month with the least rainfall in Ontario, California, is June when the rain falls for 1.2 days and typically collects 0.04" (1mm) of precipitation.

When are the longest days in Ontario?

The month with the longest days in Ontario, California, is June, with an average of 14.4h of daylight.

What month has the most sunshine in Ontario?

July has the most sunshine of the year in Ontario, California, with an average of 12.1h of sunshine.

When is the highest UV index in Ontario?

July and August, with an average maximum UV index of 7, are months with the highest UV index.

What is the warmest month in Ontario?

With an average high-temperature of 91°F (32.8°C) and an average low-temperature of 65.8°F (18.8°C), August is the warmest month in Ontario, California.

What is the least humid month in Ontario?

August is the least humid month, with an average relative humidity of 42%.

What is the coldest month in Ontario?

The coldest month in Ontario, California, is December, with an average high-temperature of 62.1°F (16.7°C) and an average low-temperature of 45.5°F (7.5°C).

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.

What is the month with the lowest UV index in Ontario?

The month with the lowest UV index is December, with an average maximum UV index of 3.

Average temperature
Ontario, CA

Average temperature - Ontario, CA

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).

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).

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Average pressure
Ontario, CA

Average pressure - Ontario, CA

The month with the highest atmospheric pressure is January (30.1").
The month with the lowest atmospheric pressure is June (29.86").

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Average wind speed
Ontario, CA

Average wind speed - Ontario, CA

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).

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Average rainfall
Ontario, CA

Average rainfall - Ontario, CA

The wettest month (with the highest rainfall) is February (1.77").
The driest month (with the least rainfall) is June (0.04").

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Average rainfall days
Ontario, CA

Average rainfall days - Ontario, CA

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).

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Average snowfall days
Ontario, CA

Average snowfall days - Ontario, CA

The month with the highest number of snowfall days is February (0.1 days).
Months with the least snowfall days are January, March, April, May, June, July, August, September, October, November and December (0 days).

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Average daylight / Average sunshine
Ontario, CA

Average daylight / Average sunshine - Ontario, CA

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

The month with the most sunshine is July (Average sunshine: 12.1h).
Months with the least sunshine are February and December (Average sunshine: 6.9).

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Average sunshine days
Ontario, CA

Average sunshine days - Ontario, CA

The month with the most sunshine days is June (28.2 days).
The month with the least sunshine days is February (21.5 days).

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Average visibility
Ontario, CA

Average visibility - Ontario, CA

Months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
Months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).

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