August weather forecast
Ontario, CA

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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 August

August, the last month of the summer in Ontario, is another hot month, with temperature in the range of an average high of 91°F (32.8°C) and an average low of 65.8°F (18.8°C).

Temperature

August is the warmest month of the year, registering average temperatures as high as 91°F (32.8°C) and as low as 65.8°F (18.8°C).

Heat index

The average heat index in August is appraised at a tropical 93.2°F (34°C). Take more preventive steps, risk of heat exhaustion and heat cramps is elevated. Long activity may culminate in heatstroke.
Research indicates the heat index considers values in shaded locales and with light winds. The heat index can potentially augment by 15 Fahrenheit (8 Celsius) degrees due to direct sunlight.
Note: The heat index, also known as 'apparent temperature' or 'feels like', is an index that combines air temperature and relative humidity to determine the human-perceived temperature equivalent. Additional elements encompassing metabolic differences, the degree of physical activity, and attire can impact the individual's perception of temperature. By being directly under the sun, it's possible for the felt temperature to increase by 15 Fahrenheit (8 Celsius) degrees. Heat index values are of high significance for children. Young ones generally face higher dangers than adults since they sweat less. Along with their large skin surface area compared totheir small bodies and increased heat production from their activities, the risks are heightened.

Humidity

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

Rainfall

In August, in Ontario, the rain falls for 1.7 days. Throughout August, 0.12" (3mm) of precipitation is accumulated. Throughout the year, there are 49.6 rainfall days, and 7.8" (198mm) of precipitation is accumulated.

Snowfall

In Ontario, snow does not fall in January, March through December.

Daylight

In Ontario, the average length of the day in August is 13h and 23min.
On the first day of August in Ontario, sunrise is at 6:02 am and sunset at 7:51 pm. On the last day of the month, sunrise is at 6:24 am and sunset at 7:17 pm PDT.

Sunshine

The average sunshine in August is 12h.

UV index

July and August, with an average maximum UV index of 7, are months with the highest UV index in Ontario. A UV Index of 6 to 7 symbolizes a high health risk from unsafe exposure to UV radiation for ordinary individuals.
Note: A maximum high UV index of 7 in August translates into the following recommendations:
Elude overexposure. Fair-skinned people could get burnt in less than 20 minutes. The Sun emits the most powerful UV radiation between 10 a.m. and 4 p.m. Try to avoid direct sunlight during this period. A wide-brimmed hat provides unparalleled sun protection for sensitive areas like the eyes, ears, and neck.
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Frequently asked questions

What month is the hottest in Ontario?

Ontario, California, records the warmest temperatures in August, averaging a high of 91°F (32.8°C) and a low of 65.8°F (18.8°C).

How hot is it in Ontario in August?

The high-temperature, in August, in Ontario, is 91°F (32.8°C), while the low-temperature averages to 65.8°F (18.8°C). In August, the average heat index (a.k.a. 'felt air temperature', 'apparent temperature'), which factors the actual air temperature with the relative humidity, is appraised at 93.2°F (34°C).

What is the least humid month in Ontario?

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

What is the average humidity in August in Ontario?

In Ontario, the average relative humidity in August is 42%.

How many days does it rain in August in Ontario?

In Ontario, California, in August, it is raining for 1.7 days, with typically 0.12" (3mm) of accumulated precipitation.

When it does not snow in Ontario?

January, March through December are months without snowfall in Ontario, California.

How many hours of daylight does Ontario have in August?

The average day length in August in Ontario is 13h and 23min.

When is the sunrise / sunset in August in Ontario?

In August, on the first day of the month, sunrise is at 6:02 am and sunset at 7:51 pm. On the last day of the month, in Ontario, California, sunrise is at 6:24 am and sunset at 7:17 pm PDT.

How long on average sun shines in August in Ontario?

In August, the average sunshine duration in Ontario, California, is 12h.

What are the months with the highest UV index in Ontario?

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

What is the UV index intensity in August in Ontario?

The average daily maximum UV index in August is 7. A UV Index reading of 6 to 7 represents a high health risk from exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in August
Ontario, CA

Average temperature in August - Ontario, CA
  • Average high temperature in August: 91°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 August: 65.8°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 in August
Ontario, CA

Average pressure in August - Ontario, CA
  • Average pressure in August: 29.88"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).

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Average wind speed in August
Ontario, CA

Average wind speed in August - Ontario, CA
  • Average wind speed in August: 4.7mph

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 humidity in August
Ontario, CA

Average humidity in August - Ontario, CA
  • Average humidity in August: 42%

The months with the highest relative humidity are March and May (54%).
The month with the lowest relative humidity is August (42%).

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Average rainfall in August
Ontario, CA

Average rainfall in August - Ontario, CA
  • Average rainfall in August: 0.12"

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 in August
Ontario, CA

Average rainfall days in August - Ontario, CA
  • Average rainfall days in August: 1.7 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).

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Average snowfall days in August
Ontario, CA

Average snowfall days in August - Ontario, CA
  • Average snowfall days in August: 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).

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Average daylight in August /
Average sunshine in August
Ontario, CA

Average daylight in August / Average sunshine in August - Ontario, CA
  • Average daylight in August: 13h and 2min

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 August: 12h and 0min

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).

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Average sunshine days in August
Ontario, CA

Average sunshine days in August - Ontario, CA
  • Average sunshine days in August: 26.8 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).

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Average UV index in August
Ontario, CA

Average UV index in August - Ontario, CA
  • Average UV index in August: 7

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).

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Average cloud cover in August
Ontario, CA

Average cloud cover in August - Ontario, CA
  • Average cloud cover in August: 5

The month with the most cloud cover is December (Cloud cover 21).
The month with the least cloud cover is August (Cloud cover 5).

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Average visibility in August
Ontario, CA

Average visibility in August - Ontario, CA
  • Average visibility in August: 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).

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Ontario, California, USA

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