July weather forecast
Naperville, IL

A covered bridge over a river along the famous Naperville Riverwalk in Naperville, Illinois
A covered bridge over a river along the famous Naperville Riverwalk in Naperville, Illinois

Weather in July

July, the same as June, is a moderately hot summer month in Naperville, Illinois, with average temperature fluctuating between 81.7°F (27.6°C) and 65.1°F (18.4°C).

Temperature

With an average high-temperature of 81.7°F (27.6°C) and an average low-temperature of 65.1°F (18.4°C), July is the warmest month.

Heat index

In July, the average heat index is evaluated at a tropical 88°F (31.1°C). Exhaustion is likely with prolonged exposure and activity. Sustaining activity may result in heat cramps.
Note that heat index values are valued for light wind and location in the shade. Exposure to direct sunshine can increase heat index values by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'feels like', 'apparent temperature', 'felt air temperature', or 'real feel', combines air temperature and relative humidity to represent a human perceived temperature equivalent. Additional factors like wind, differences in body mass, height, and shape, clothing, and activity influence one's weather impression. 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 especially crucial for babies and toddlers. Young children are generally more endangered than adults, as they usually less sweat. And also, due to larger skin surface relative to their small bodies and higher heat production as a result of their activity.

Humidity

In July, the average relative humidity is 80%.

Rainfall

In July, in Naperville, the rain falls for 17.3 days. Throughout July, 2.05" (52mm) of precipitation is accumulated. Throughout the year, in Naperville, there are 132.2 rainfall days, and 16.22" (412mm) of precipitation is accumulated.

Snowfall

May through September are months without snowfall in Naperville.

Daylight

The average length of the day in July is 14.9h.

Sunshine

Months with the most sunshine in Naperville are July and August, with an average of 10h of sunshine.

UV index

Months with the highest UV index are June through August, with an average maximum UV index of 6. A UV Index value of 6 to 7 symbolizes a high health vulnerability from unprotected exposure to the Sun's UV rays for the average person.
Note: In July, the average maximum UV index of 6 translate into the following recommendations:
Take precautions against overexposure. Fair-skinned people may get burned in less than 20 minutes. Seek shade and minimize exposure to direct Sun in a period between 10 a.m. and 4 p.m. when UV radiation is most intense; keep in mind that shade structures like parasols or canopies do not provide perfect sun protection. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects.
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FAQ

What is the warmest month in Naperville?

July is the warmest month in Naperville, with an average high-temperature of 81.7°F (27.6°C) and an average low-temperature of 65.1°F (18.4°C).

What is the temperature in July in Naperville?

The average high-temperature, in July, in Naperville, Illinois, is 81.7°F (27.6°C), while the average low-temperature is 65.1°F (18.4°C). The average heat index (a.k.a. 'apparent temperature', 'feels like'), which represents the influence of relative humidity on air temperature, in July is evaluated at 88°F (31.1°C).

What is the average humidity in July in Naperville?

In July, the average relative humidity is 80%.

How many days does it rain in July in Naperville?

In July, in Naperville, Illinois, the rain falls for 17.3 days. Throughout July, 2.05" (52mm) of precipitation is accumulated.

When it does not snow in Naperville?

In Naperville snow does not fall in May through September.

How many hours of daylight does Naperville have in July?

In Naperville, Illinois, the average length of the day in July is 14.9h.

What are the months with the most sunshine in Naperville?

Months with the most sunshine in Naperville are July and August, with an average of 10h of sunshine.

How long on average sun shines in July in Naperville?

In Naperville, the average sunshine in July is 10h.

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

Months with the highest UV index in Naperville, Illinois, are June through August, with an average maximum UV index of 6.

How high is the UV index in July in Naperville?

The average daily maximum UV index in July in Naperville is 6. A UV Index estimate of 6 to 7 represents a high health vulnerability from unprotected exposure to the UV radiation.

Average temperature in July
Naperville, IL

Average temperature in July - Naperville, IL
  • Average high temperature in July: 81.7°F

The warmest month (with the highest average high temperature) is July (81.7°F).
The month with the lowest average high temperature is January (28.4°F).

  • Average low temperature in July: 65.1°F

The month with the highest average low temperature is July (65.1°F).
The coldest month (with the lowest average low temperature) is January (17.1°F).

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Average pressure in July
Naperville, IL

Average pressure in July - Naperville, IL
  • Average pressure in July: 29.97"

The month with the highest atmospheric pressure is January (30.11").
The month with the lowest atmospheric pressure is June (29.92").

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Average wind speed in July
Naperville, IL

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

The windiest month (with the highest average wind speed) is January (9.7mph).
The calmest month (with the lowest average wind speed) is August (6mph).

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Average humidity in July
Naperville, IL

Average humidity in July - Naperville, IL
  • Average humidity in July: 80%

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

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Average rainfall in July
Naperville, IL

Average rainfall in July - Naperville, IL
  • Average rainfall in July: 2.05"

The wettest month (with the highest rainfall) is May (2.09").
The driest month (with the least rainfall) is December (0.71").

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Average rainfall days in July
Naperville, IL

Average rainfall days in July - Naperville, IL
  • Average rainfall days in July: 17.3 days

The month with the highest number of rainy days is July (17.3 days).
The month with the least rainy days is February (4.4 days).

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Average snowfall in July
Naperville, IL

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

The month with the highest snowfall is January (1.85").
Months with the least snowfall are May, June, July, August and September (0").

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Average snowfall days in July
Naperville, IL

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

The month with the highest number of snowfall days is January (11.1 days).
Months with the least snowfall days are June, July, August and September (0 days).

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

Average daylight in July / Average sunshine in July - Naperville, IL
  • Average daylight in July: 14.9h

The month with the longest days is June (Average daylight: 15.2h).
The month with the shortest days is December (Average daylight: 9.2h).

  • Average sunshine in July: 10h

Months with the most sunshine are July and August (Average sunshine: 10h).
The month with the least sunshine is January (Average sunshine: 3.8h).

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Average sunshine days in July
Naperville, IL

Average sunshine days in July - Naperville, IL
  • Average sunshine days in July: 10.2 days

The month with the most sunshine days is November (19.6 days).
The month with the least sunshine days is July (10.2 days).

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Average UV index in July
Naperville, IL

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

Months with the highest UV index are June, July and August (UV index 6).
Months with the lowest UV index are January and December (UV index 1).

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Average cloud cover in July
Naperville, IL

Average cloud cover in July - Naperville, IL
  • Average cloud cover in July: 32

The month with the most cloud cover is January (Cloud cover 60).
Months with the least cloud cover are August and September (Cloud cover 31).

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Average visibility in July
Naperville, IL

Average visibility in July - Naperville, IL
  • Average visibility in July: 6mi

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

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