August weather forecast
Harrisburg, IL

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Weather in August

August in Harrisburg, Illinois witnesses the grandeur of a typical late summer. Temperatures remain comparably high, ranging from 66°F (18.9°C) to 85.6°F (29.8°C), albeit a slight dip from July. The hot and sunny weather forms the perfect backdrop for enjoying summer festivities and water sports, although the scorching sun might call for necessary precautions. Even though rainfall occurrences are relatively low, they do offer a refreshing change from the enduring heat. As August concludes, temperatures start to decline, marking the imminent arrival of Autumn.

Temperature

A minor adjustment in Harrisburg's average high-temperature is noted with the start of August, touching a warm 85.6°F (29.8°C) from July's 87.3°F (30.7°C). Harrisburg throughout August, records an average low-temperature of 66°F (18.9°C).

Heat index

The heat index for August is evaluated at a sweltering 96.8°F (36°C). Take extra safety measures to prevent heat exhaustion and heat cramps. Heatstroke could follow lengthy activity.
Realize that the values for the heat index are set for shaded places and light winds. The presence of direct sunlight can raise the heat index values by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel' or 'apparent temperature', is a numerical representation of warmth when taking temperature and moisture levels into account. The impact of weather is personal, differing among a variety of people based on differences in body mass, height, and the level of physical exertion. Direct exposure to sun rays can potentially augment the heat sensation, elevating the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are extremely significant for children. Young people are generally more susceptible than adults because they perspire less. Furthermore, their proportionally larger skin surface to their petite bodies and the increased heat output from their actions add to the risk.
To prevent overheating and help regulate its internal temperature, the human body sweat and rely on the evaporation to cool down. An increase in relative humidity retards evaporation, subsequently reducing the body's heat removal rate and leading to a sensation of being overly warm. As the body gains more heat than it can dissipate, there's a risk of increasing temperatures and resultant overheating.

Humidity

The average relative humidity in August in Harrisburg is 76%.

Rainfall

In Harrisburg, Illinois, in August, it is raining for 13.8 days, with typically 2.52" (64mm) of accumulated precipitation. In Harrisburg, during the entire year, the rain falls for 158.6 days and collects up to 36.02" (915mm) of precipitation.

Snowfall

In Harrisburg, snow does not fall in May through September.

Daylight

In August, the average length of the day is 13h and 34min.
On the first day of August in Harrisburg, Illinois, sunrise is at 5:58 am and sunset at 8:02 pm. On the last day of the month, sunrise is at 6:24 am and sunset at 7:24 pm CDT.

Sunshine

The average sunshine in August is 10.3h.

UV index

The months with the highest UV index are May through August, with an average maximum UV index of 6. A UV Index value of 6 to 7 symbolizes a high threat to health from exposure to the Sun's UV radiation for the average person.
Note: The UV index of 6 in August translates into these instructions:
Implement precautions and maintain sun safety methods. Avoidance of sunburn is demanded. During the period from 10 a.m. to 4 p.m., UV radiation is highest. Try to avoid direct sunlight during these hours. Opt for tightly woven and loose clothing to enhance protection from the Sun.
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Frequently asked questions

Is it hot in Harrisburg during August?

During August, Harrisburg experiences an average high-temperature of 85.6°F (29.8°C) and a low-temperature of 66°F (18.9°C). The average heat index (a.k.a. 'felt air temperature', 'real feel'), which combines relative humidity and air temperature, in August is evaluated at 96.8°F (36°C).

What is the average humidity in August in Harrisburg?

In Harrisburg, the average relative humidity in August is 76%.

How much does it rain in Harrisburg in August?

In Harrisburg, Illinois, in August, during 13.8 rainfall days, 2.52" (64mm) of precipitation is typically accumulated.

When it does not snow in Harrisburg?

In Harrisburg, snow does not fall in May through September.

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

The average day length in August is 13h and 34min.

When are sunrise and sunset in August in Harrisburg?

On the first day of August in Harrisburg, sunrise is at 5:58 am and sunset at 8:02 pm. On the last day of the month, sunrise is at 6:24 am and sunset at 7:24 pm CDT.

How many hours of sunshine does Harrisburg have in August?

The average sunshine duration in August is 10.3h.

What is the month with the highest UV index in Harrisburg?

The months with the highest UV index in Harrisburg, Illinois, are May through August, with an average maximum UV index of 6.

How high is the UV index in August in Harrisburg?

In August, the average daily maximum UV index is 6. A UV Index of 6 to 7 symbolizes a high hazard to health from exposure to the Sun's UV radiation.
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
Harrisburg, IL

Average temperature in August - Harrisburg, IL
  • Average high temperature in August: 85.6°F

The warmest month (with the highest average high temperature) is July (87.3°F).
The month with the lowest average high temperature is January (39.7°F).

  • Average low temperature in August: 66°F

The month with the highest average low temperature is July (68.5°F).
The coldest month (with the lowest average low temperature) is January (26.2°F).

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Average pressure in August
Harrisburg, IL

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

The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.94"Hg).

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Average wind speed in August
Harrisburg, IL

Average wind speed in August - Harrisburg, IL
  • Average wind speed in August: 5.8mph

The windiest months (with the highest average wind speed) are January and February (9.4mph).
The calmest months (with the lowest average wind speed) are July and August (5.8mph).

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Average humidity in August
Harrisburg, IL

Average humidity in August - Harrisburg, IL
  • Average humidity in August: 76%

The month with the highest relative humidity is May (79%).
The month with the lowest relative humidity is October (70%).

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Average rainfall in August
Harrisburg, IL

Average rainfall in August - Harrisburg, IL
  • Average rainfall in August: 2.52"

The wettest month (with the highest rainfall) is April (4.8").
The driest month (with the least rainfall) is September (1.57").

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Average rainfall days in August
Harrisburg, IL

Average rainfall days in August - Harrisburg, IL
  • Average rainfall days in August: 13.8 days

The month with the highest number of rainy days is May (18.5 days).
The month with the least rainy days is November (9.7 days).

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Average snowfall in August
Harrisburg, IL

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

The month with the highest snowfall is January (1.73").
The months with the least snowfall are May, June, July, August and September (0").

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Average snowfall days in August
Harrisburg, IL

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

The month with the highest number of snowfall days is January (5.3 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
Harrisburg, IL

Average daylight in August / Average sunshine in August - Harrisburg, IL
  • Average daylight in August: 13h and 4min

The month with the longest days is June (Average daylight: 14h and 42min).
The month with the shortest days is December (Average daylight: 9h and 36min).

  • Average sunshine in August: 10h and 2min

The month with the most sunshine is June (Average sunshine: 10h and 36min).
The month with the least sunshine is January (Average sunshine: 4h and 36min).

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Average sunshine days in August
Harrisburg, IL

Average sunshine days in August - Harrisburg, IL
  • Average sunshine days in August: 15 days

The month with the most sunshine days is October (19.5 days).
The month with the least sunshine days is May (9.9 days).

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Average UV index in August
Harrisburg, IL

Average UV index in August - Harrisburg, IL
  • Average UV index in August: 6

The months with the highest UV index are May, June, July and August (UV index 6).
The months with the lowest UV index are January, February and December (UV index 2).

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Average cloud cover in August
Harrisburg, IL

Average cloud cover in August - Harrisburg, IL
  • Average cloud cover in August: 29

The months with the most cloud cover are January and February (Cloud cover 51).
The months with the least cloud cover are June and September (Cloud cover 28).

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Average visibility in August
Harrisburg, IL

Average visibility in August - Harrisburg, IL
  • 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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Harrisburg, Illinois, USA

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