August weather forecast
Ottawa, IL

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Weather in August

The last month of the summer, August, is also a moderately hot month in Ottawa, Illinois, with an average temperature fluctuating between 79.3°F (26.3°C) and 62.1°F (16.7°C).

Temperature

In Ottawa, August's average high-temperature stands at a still moderately hot 79.3°F (26.3°C), closely related to the preceding month. In August, Ottawa reports a consistent average low-temperature of 62.1°F (16.7°C) during the nights.

Humidity

In August, the average relative humidity in Ottawa is 84%.

Rainfall

In Ottawa, in August, it is raining for 18.3 days, with typically 2.95" (75mm) of accumulated precipitation. Throughout the year, in Ottawa, there are 166.3 rainfall days, and 35.35" (898mm) of precipitation is accumulated.

Snowfall

May through September are months without snowfall in Ottawa, Illinois.

Daylight

In Ottawa, the average length of the day in August is 13h and 47min.
On the first day of the month, sunrise is at 5:51 am and sunset at 8:12 pm. On the last day of August, in Ottawa, sunrise is at 6:21 am and sunset at 7:29 pm CDT.

Sunshine

In Ottawa, the average sunshine in August is 9.7h.

UV index

The average daily maximum UV index in August is 5. A UV Index estimate of 3 to 5 represents a moderate threat to health from exposure to the Sun's UV radiation for ordinary individuals.
Note: A maximum high daily UV index of 5 during August translates into the following directions:
Ensure safety - Imperative it is to shield skin and eyes from damage. To guard against the harmful effects of the Sun, minimize exposure during midday. Prioritize a wide-brim hat for comprehensive sun defense for your face, neck, eyes, and ears.
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Frequently asked questions

What is the average August temperature in Ottawa?

The high-temperature, in August, in Ottawa, records 79.3°F (26.3°C), while the low-temperature is 62.1°F (16.7°C). In July, the average heat index (a.k.a. 'real feel', 'feels like'), which represents the influence of relative humidity on air temperature, is appraised at 87.8°F (31°C).

What is the average humidity in August in Ottawa?

In Ottawa, the average relative humidity in August is 84%.

How many days does it rain in August in Ottawa?

In Ottawa, during August, the rain falls for 18.3 days and regularly aggregates up to 2.95" (75mm) of precipitation.

When it does not snow in Ottawa?

May through September are months without snowfall in Ottawa, Illinois.

What is the average length of the day in August in Ottawa?

The average day length in August in Ottawa, Illinois, is 13h and 47min.

When is the sunrise / sunset in August in Ottawa?

On the first day of August in Ottawa, Illinois, sunrise is at 5:51 am and sunset at 8:12 pm. On the last day of the month, sunrise is at 6:21 am and sunset at 7:29 pm CDT.

How long on average sun shines in August in Ottawa?

The average sunshine duration in August in Ottawa, Illinois, is 9.7h.

What is the UV index reading in August in Ottawa?

The average daily maximum UV index in August is 5. A UV Index of 3 to 5 symbolizes a moderate health threat from exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in August
Ottawa, IL

Average temperature in August - Ottawa, IL
  • Average high temperature in August: 79.3°F

The warmest month (with the highest average high temperature) is July (81°F).
The month with the lowest average high temperature is January (29.1°F).

  • Average low temperature in August: 62.1°F

The month with the highest average low temperature is July (64.2°F).
The coldest month (with the lowest average low temperature) is January (17.2°F).

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Average pressure in August
Ottawa, IL

Average pressure in August - Ottawa, IL
  • Average pressure in August: 29.98"Hg

The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).

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Average wind speed in August
Ottawa, IL

Average wind speed in August - Ottawa, IL
  • Average wind speed in August: 6.2mph

The windiest month (with the highest average wind speed) is April (10.2mph).
The calmest month (with the lowest average wind speed) is August (6.2mph).

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Average humidity in August
Ottawa, IL

Average humidity in August - Ottawa, IL
  • Average humidity in August: 84%

The month with the highest relative humidity is July (85%).
The month with the lowest relative humidity is October (72%).

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Average rainfall in August
Ottawa, IL

Average rainfall in August - Ottawa, IL
  • Average rainfall in August: 2.95"

The wettest month (with the highest rainfall) is May (5").
The driest month (with the least rainfall) is November (1.81").

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Average rainfall days in August
Ottawa, IL

Average rainfall days in August - Ottawa, IL
  • Average rainfall days in August: 18.3 days

The month with the highest number of rainy days is July (19.9 days).
The month with the least rainy days is February (6.2 days).

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Average snowfall in August
Ottawa, IL

Average snowfall in August - Ottawa, IL
  • Average snowfall in August: 0"

The month with the highest snowfall is February (5.08").
The months with the least snowfall are May, June, July, August and September (0").

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Average snowfall days in August
Ottawa, IL

Average snowfall days in August - Ottawa, IL
  • Average snowfall days in August: 0 days

The month with the highest number of snowfall days is January (12.9 days).
The months with the least snowfall days are May, June, July, August and September (0 days).

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Average daylight in August /
Average sunshine in August
Ottawa, IL

Average daylight in August / Average sunshine in August - Ottawa, IL
  • Average daylight in August: 13h and 5min

The month with the longest days is June (Average daylight: 15h and 6min).
The month with the shortest days is December (Average daylight: 9h and 12min).

  • Average sunshine in August: 9h and 4min

The month with the most sunshine is June (Average sunshine: 9h and 48min).
The month with the least sunshine is January (Average sunshine: 3h and 54min).

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Average sunshine days in August
Ottawa, IL

Average sunshine days in August - Ottawa, IL
  • Average sunshine days in August: 9.9 days

The month with the most sunshine days is November (17 days).
The month with the least sunshine days is July (7.2 days).

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Average UV index in August
Ottawa, IL

Average UV index in August - Ottawa, IL
  • Average UV index in August: 5

The months with the highest UV index are June and July (UV index 6).
The months with the lowest UV index are January and December (UV index 1).

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Average cloud cover in August
Ottawa, IL

Average cloud cover in August - Ottawa, IL
  • Average cloud cover in August: 33

The month with the most cloud cover is January (Cloud cover 59).
The month with the least cloud cover is September (Cloud cover 32).

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Average visibility in August
Ottawa, IL

Average visibility in August - Ottawa, IL
  • Average visibility in August: 5mi

The months with the highest visibility are March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are January, February, July and August (5mi).

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Ottawa, Illinois, USA

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