Naperville
Illinois, USA
Long-term weather forecast
Long-term weather forecast

July weather forecast and climate
Naperville, IL

The scenic view of a covered bridge over a river along the famous Naperville Riverwalk in Naperville, Illinois, reflections in the below water
The scenic view of a covered bridge over a river along the famous Naperville Riverwalk in Naperville, Illinois, reflections in the below water
July, like June, in Naperville, Illinois, is another warm summer month, with average temperature fluctuating between 81.7°F (27.6°C) and 65.1°F (18.4°C).

Temperature

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

Heat index

In July, the average heat index is estimated at a tropical 88°F (31.1°C). Exhaustion is likely with prolonged exposure and activity. Sustaining activity may result in heat cramps.
Take into consideration that the heat index values are calculated for shade and light wind conditions. 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', 'felt air temperature', 'apparent temperature', or 'real feel', is a measure of how hot it feels when the actual air humidity is factored in. This effect is subjective, depending on the activity and individual's heat perception influenced by various reasons (differences in body mass, height, and shape, clothing, metabolic differences). 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 particularly important for children. Children are often less aware of the need to rest and re-hydrate. Thirst is a late sign of dehydration - it is vital to remain hydrated, particularly during prolonged physical activities.

Humidity

In July, the average relative humidity is 80%.

Rainfall

In Naperville, during July, the rain falls for 17.3 days and regularly aggregates up to 2.05" (52mm) of precipitation. In Naperville, during the entire year, the rain falls for 132.2 days and collects up to 16.22" (412mm) of precipitation.

Snowfall

May through September are months without snowfall.

Daylight

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

Sunshine

Months with the most sunshine in Naperville, Illinois, 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 the exposure to the Sun's UV rays for the average person.
Note: The average daily UV index of 6 transform into the following instructions:
Take precautions and adopt sun safety practices. Protection against sunburn is obliged. The Sun's UV radiation is most powerful between 10 a.m. and 4 p.m. To the extent possible, limit exposure to the direct sun during these hours. A wide-brim hat offers excellent sun protection for eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. Tightly woven, loose-fitting clothes provide additional protection from the Sun.

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, 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. 'feels like', 'real feel'), that represents influence of the relative humidity to air temperaure, in July is estimated at 88°F (31.1°C).

What is the average humidity in July in Naperville?

In Naperville, Illinois, the average relative humidity in July is 80%.

How much does it rain in Naperville in July?

In Naperville, Illinois, in July, it is raining for 17.3 days, with typically 2.05" (52mm) of accumulated precipitation.

When it does not snow in Naperville?

May through September are months without snowfall in Naperville.

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

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

What is the month with the most sunshine in Naperville?

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

How many hours of sunshine does Naperville have in July?

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

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

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

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 reading of 6 to 7 represents a high health threat from the exposure to the Sun's UV rays.
Average temperature in July - Naperville, IL
  • Average high temperature in July: 27.6°C

The warmest month (with the highest average high temperature) is July (27.6°C).
The month with the lowest average high temperature is January (-2°C).

  • Average low temperature in July: 18.4°C

The month with the highest average low temperature is July (18.4°C).
The coldest month (with the lowest average low temperature) is January (-8.3°C).

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%).

Average rainfall in July - Naperville, IL
  • Average rainfall in July: 52mm

The wettest month (with the highest rainfall) is May (53mm).
The driest month (with the lowest rainfall) is December (18mm).

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 lowest number of rainy days is February (4.4 days).

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

The month with the highest snowfall is January (47mm).
Months with the lowest snowfall are May, June, July, August and September (0mm).

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 lowest number of snowfall days are June, July, August and September (0 days).

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 shortest days is December (Average daylight: 9.2h).

  • Average sunshine in July: 10h

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

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).