August weather forecast
Belleville, IL

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Weather in August

There is a subtle transition to be felt as August unfolds in Belleville. Capping off the last of the high-summer months, August heralds shorter daylight hours yet remains comfortably warm. The city retains a high relative humidity, reinforcing its distinct summertime atmosphere. Belleville continues to bask in the dying embers of a vibrant summer before segueing into September's mellow warmth. With a decrease in wind gustiness, outdoor experiences remain pleasant and inviting.

Temperature

With August's arrival, Belleville, Illinois, notes an average high-temperature of a still moderately hot 84.6°F (29.2°C), closely following the trend of the preceding month. Nighttime temperature in Belleville experiences an average drop to a refreshing 66°F (18.9°C) in August.

Heat index

For most parts of August, the heat index is estimated at a fiery hot 95°F (35°C). Extra precautions are necessary, heat cramps and heat exhaustion are plausible outcomes. Extended activity could lead to heatstroke.
Keep in mind the heat index values are meant for areas in shade and with light wind. The heat index may experience an enhancement of 15 Fahrenheit (8 Celsius) degrees under direct sunlight.
Note: The heat index, also known as 'feels like' or 'real feel', is an estimation of the warmth sensation when considering humidity levels. The influence of weather is personal, differing among a variety of individuals based on differences in body mass, stature, and the level of physical activity. Bear in mind that direct sunshine exposure increases weather impact, and may raise heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are primarily vital for children. Young ones are generally at greater risk than adults due to their limited sweating ability. In addition, their large skin surface relative to their small bodies and higher heat production from their activities add to their vulnerability.
For the human body, perspiration is the go-to method to regulate temperature, using sweat's evaporation to dissipate warmth. Increased relative humidity interferes with body cooling by slowing the rate of evaporation, resulting in a slower body cooling rate and a heightened feeling of heat. Heat-related challenges, like dehydration, can be anticipated when body heat isn't managed effectively.

Humidity

The average relative humidity in August is 78%.

Rainfall

In August, the rain falls for 12.9 days. Throughout August, 3.31" (84mm) of precipitation is accumulated. Throughout the year, in Belleville, there are 147.1 rainfall days, and 35.43" (900mm) of precipitation is accumulated.

Snowfall

In Belleville, snow does not fall in April through October.

Daylight

In August, the average length of the day in Belleville is 13h and 37min.
On the first day of the month, sunrise is at 6:02 am and sunset at 8:09 pm. On the last day of August, sunrise is at 6:29 am and sunset at 7:30 pm CDT.

Sunshine

In August, the average sunshine in Belleville is 10h.

UV index

May through August, with an average maximum UV index of 6, are months with the highest UV index in Belleville. A UV Index of 6 to 7 symbolizes a high health hazard from exposure to the Sun's UV radiation for the ordinary person.
Note: The UV index of 6 in August translates into these instructions:
Stick with precautions and abide by sun safety procedures. Evading sunburn is essential. Between 10 a.m. and 4 p.m., UV radiation is strongest. Make an effort to avoid direct sunlight during this time, remembering that shade structures may not provide full sun protection. Experience reduced UV exposure by about half when donning a wide-brim hat.
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Frequently asked questions

How hot does it get in Belleville in August?

In Belleville, in August, the average high-temperature is 84.6°F (29.2°C), and the average low-temperature is 66°F (18.9°C). In August, the average heat index (a.k.a. 'real feel', 'apparent temperature'), which represents the influence of relative humidity on air temperature, is estimated at 95°F (35°C).

What is the average humidity in August in Belleville?

In Belleville, Illinois, the average relative humidity in August is 78%.

How many days does it rain in August in Belleville?

In Belleville, in August, during 12.9 rainfall days, 3.31" (84mm) of precipitation is typically accumulated.

When it does not snow in Belleville?

April through October are months without snowfall.

How many hours of daylight does Belleville have in August?

In August, the average day length in Belleville is 13h and 37min.

What time are sunrise and sunset in August in Belleville?

In August, on the first day of the month, sunrise is at 6:02 am and sunset at 8:09 pm. On the last day of the month, sunrise is at 6:29 am and sunset at 7:30 pm CDT.

How long on average sun shines in August in Belleville?

The average sunshine duration in August is 10h.

When is the highest UV index in Belleville?

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

How high is the UV index in August in Belleville?

In August, the average daily maximum UV index in Belleville, Illinois, is 6. A UV Index of 6 to 7 symbolizes a high hazard to health from unsafe 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
Belleville, IL

Average temperature in August - Belleville, IL
  • Average high temperature in August: 84.6°F

The warmest month (with the highest average high temperature) is July (85.8°F).
The month with the lowest average high temperature is January (37.8°F).

  • Average low temperature in August: 66°F

The month with the highest average low temperature is July (68.4°F).
The coldest month (with the lowest average low temperature) is January (24.8°F).

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Average pressure in August
Belleville, IL

Average pressure in August - Belleville, 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 (29.92"Hg).

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Average wind speed in August
Belleville, IL

Average wind speed in August - Belleville, IL
  • Average wind speed in August: 5.7mph

The windiest month (with the highest average wind speed) is January (9.4mph).
The calmest month (with the lowest average wind speed) is July (5.6mph).

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Average humidity in August
Belleville, IL

Average humidity in August - Belleville, IL
  • Average humidity in August: 78%

The months with the highest relative humidity are May and July (79%).
The month with the lowest relative humidity is October (71%).

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Average rainfall in August
Belleville, IL

Average rainfall in August - Belleville, IL
  • Average rainfall in August: 3.31"

The wettest month (with the highest rainfall) is May (4.37").
The driest month (with the least rainfall) is February (1.93").

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Average rainfall days in August
Belleville, IL

Average rainfall days in August - Belleville, IL
  • Average rainfall days in August: 12.9 days

The month with the highest number of rainy days is May (16.4 days).
The month with the least rainy days is January (6.8 days).

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Average snowfall in August
Belleville, IL

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

The month with the highest snowfall is January (2.4").
The months with the least snowfall are April, May, June, July, August, September and October (0").

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Average snowfall days in August
Belleville, IL

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

The month with the highest number of snowfall days is January (7.3 days).
The months with the least snowfall days are May, June, July and August (0 days).

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

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

The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 30min).

  • Average sunshine in August: 10h and 0min

The month with the most sunshine is June (Average sunshine: 10h and 18min).
The month with the least sunshine is January (Average sunshine: 4h and 30min).

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Average sunshine days in August
Belleville, IL

Average sunshine days in August - Belleville, IL
  • Average sunshine days in August: 16.2 days

The month with the most sunshine days is October (18.3 days).
The month with the least sunshine days is May (12.3 days).

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Average UV index in August
Belleville, IL

Average UV index in August - Belleville, 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
Belleville, IL

Average cloud cover in August - Belleville, IL
  • Average cloud cover in August: 30

The month with the most cloud cover is January (Cloud cover 52).
The month with the least cloud cover is June (Cloud cover 29).

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Average visibility in August
Belleville, IL

Average visibility in August - Belleville, 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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Belleville, Illinois, USA

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