July weather forecast
Joliet, IL

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A unique shot of cars, trees, and buildings along a street in the town of Joliet, Illinois
A unique shot of cars, trees, and buildings along a street in the town of Joliet, Illinois

Weather in July

July is characterized as the climax of the summer season in Joliet. Balmy temperatures are the benchmark for July, and a high of 81.3°F (27.4°C) is typically recorded, the year's hottest. Despite the heat, relative humidity remains high throughout the month. More than half the day enjoys broad daylight and the reduction in wind speed provides for calm, steady weather conditions.

Temperature

The average temperatures reach their apex in July, averaging 81.3°F (27.4°C) at the high end and 64.8°F (18.2°C) at the low end.

Heat index

The heat index for July is calculated to be a hot 87.8°F (31°C). Long-standing exposure and activity could induce a feeling of tiredness and lead to heat cramps.
Heat index values are typically calculated for conditions of shade and a light breeze. Under direct sunshine, the heat index values might be elevated by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'felt air temperature' or 'real feel', is a numerical representation of warmth when taking temperature and moisture levels into account. One's weather perception can be influenced by a range of factors including metabolic differences, being pregnant, and their level of physical activity. Direct sun exposure is noteworthy in its ability to escalate the felt temperature, potentially adding 15 Fahrenheit (8 Celsius) degrees to the heat index. Heat index values are of high significance for children. Kids are usually in more danger than grown-ups as they tend to sweat less. Plus, their bigger skin surface in relation to their small frames and increased heat generation due to their activity level make them more susceptible.

Humidity

In July, the average relative humidity is 82%.

Rainfall

In Joliet, in July, during 17.9 rainfall days, 3.46" (88mm) of precipitation is typically accumulated. In Joliet, during the entire year, the rain falls for 153.6 days and collects up to 32.72" (831mm) of precipitation.

Snowfall

In Joliet, snow does not fall in May through October.

Daylight

In July, the average length of the day in Joliet is 14h and 50min.
On the first day of the month, sunrise is at 5:22 am and sunset at 8:30 pm. On the last day of July, in Joliet, Illinois, sunrise is at 5:46 am and sunset at 8:10 pm CDT.

Sunshine

In Joliet, the average sunshine in July is 9.6h.

UV index

The months with the highest UV index are June and July, with an average maximum UV index of 6. A UV Index reading of 6 to 7 represents a high threat to health from unprotected exposure to Sun's UV rays for ordinary individuals.
Note: The daily high UV index of 6 in July translates into this advice:
Use measures and accept sun safety conventions. Guarding against skin and eye trauma is of high priority. Avoid direct Sun exposure and seek shade from 10 a.m. to 4 p.m., the period of highest UV radiation. Remember, however, that not all shade structures offer full protection. Outfit yourself in sun-safe attire, like long sleeves, pants, a hat, and UV-blocking sunglasses.
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Frequently asked questions

What part of the year is the hottest in Joliet?

Joliet, Illinois, witnesses the warmest weather in July, with temperatures averaging a high of 81.3°F (27.4°C) and a low of 64.8°F (18.2°C).

What is the usual temperature for Joliet in July?

In Joliet, 81.3°F (27.4°C) is the average high-temperature and 64.8°F (18.2°C) is the average low-temperature during July. In July, the average heat index (a.k.a. 'apparent temperature', 'felt air temperature'), which factors the actual air temperature with the relative humidity, is calculated to be 87.8°F (31°C).

What is the average humidity in July in Joliet?

The average relative humidity in July in Joliet is 82%.

How many days does it rain in July in Joliet?

In Joliet, in July, it is raining for 17.9 days, with typically 3.46" (88mm) of accumulated precipitation.

When it does not snow in Joliet?

In Joliet, Illinois, snow does not fall in May through October.

What is the average length of the day in July in Joliet?

In Joliet, the average day length in July is 14h and 50min.

When is the sunrise / sunset in July in Joliet?

On the first day of July in Joliet, sunrise is at 5:22 am and sunset at 8:30 pm. On the last day of the month, sunrise is at 5:46 am and sunset at 8:10 pm CDT.

How long on average sun shines in July in Joliet?

The average sunshine duration in July in Joliet, Illinois, is 9.6h.

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

June and July, with an average maximum UV index of 6, are months with the highest UV index in Joliet, Illinois.

What is the UV index intensity in July in Joliet?

In July, the average daily maximum UV index is 6. A UV Index of 6 to 7 symbolizes a high health risk 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 July
Joliet, IL

Average temperature in July - Joliet, IL
  • Average high temperature in July: 81.3°F

The warmest month (with the highest average high temperature) is July (81.3°F).
The month with the lowest average high temperature is January (29.3°F).

  • Average low temperature in July: 64.8°F

The month with the highest average low temperature is July (64.8°F).
The coldest month (with the lowest average low temperature) is January (17.4°F).

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Average pressure in July
Joliet, IL

Average pressure in July - Joliet, IL
  • Average pressure in July: 29.97"Hg

The month with the highest atmospheric pressure is January (30.12"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).

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Average wind speed in July
Joliet, IL

Average wind speed in July - Joliet, IL
  • Average wind speed in July: 6.2mph

The windiest month (with the highest average wind speed) is April (9.7mph).
The calmest month (with the lowest average wind speed) is August (5.9mph).

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Average humidity in July
Joliet, IL

Average humidity in July - Joliet, IL
  • Average humidity in July: 82%

The month with the highest relative humidity is February (83%).
The month with the lowest relative humidity is October (73%).

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Average rainfall in July
Joliet, IL

Average rainfall in July - Joliet, IL
  • Average rainfall in July: 3.46"

The wettest month (with the highest rainfall) is May (4.41").
The driest month (with the least rainfall) is February (1.61").

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Average rainfall days in July
Joliet, IL

Average rainfall days in July - Joliet, IL
  • Average rainfall days in July: 17.9 days

The month with the highest number of rainy days is July (17.9 days).
The month with the least rainy days is February (5.7 days).

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Average snowfall in July
Joliet, IL

Average snowfall in July - Joliet, IL
  • Average snowfall in July: 0"

The month with the highest snowfall is January (4.33").
The months with the least snowfall are May, June, July, August, September and October (0").

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Average snowfall days in July
Joliet, IL

Average snowfall days in July - Joliet, IL
  • Average snowfall days in July: 0 days

The month with the highest number of snowfall days is January (11.9 days).
The months with the least snowfall days are May, June, July, August and September (0 days).

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Average daylight in July /
Average sunshine in July
Joliet, IL

Average daylight in July / Average sunshine in July - Joliet, IL
  • Average daylight in July: 14h 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 July: 9h and 4min

The month with the most sunshine is August (Average sunshine: 9h and 42min).
The month with the least sunshine is January (Average sunshine: 3h and 42min).

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Average sunshine days in July
Joliet, IL

Average sunshine days in July - Joliet, IL
  • Average sunshine days in July: 10.8 days

The month with the most sunshine days is November (18.1 days).
The month with the least sunshine days is June (10.4 days).

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Average UV index in July
Joliet, IL

Average UV index in July - Joliet, IL
  • Average UV index in July: 6

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 July
Joliet, IL

Average cloud cover in July - Joliet, IL
  • Average cloud cover in July: 36

The month with the most cloud cover is January (Cloud cover 60).
The months with the least cloud cover are August and September (Cloud cover 34).

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Average visibility in July
Joliet, IL

Average visibility in July - Joliet, IL
  • Average visibility in July: 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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Joliet, Illinois, USA

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