July weather forecast
Chesterfield, IL

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Weather in July

July, the same as June, is a moderately hot summer month in Chesterfield, Illinois, with temperature in the range of an average high of 83.8°F (28.8°C) and an average low of 66.9°F (19.4°C).

Temperature

July, characterized by an average high temperature of 83.8°F (28.8°C) and a low temperature of 66.9°F (19.4°C), is generally the warmest month.

Heat index

In July, the heat index is evaluated at a very hot 95°F (35°C). Emphasize additional safety, risk of heat cramps and heat exhaustion is high. Continuous activity might result in heatstroke.
Heat index details are generally centered around shaded locations and a mild breeze. With exposure to direct sunlight, the heat index may be increased by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel' or 'feels like', is found by incorporating humidity levels into the air temperature measurement. The effect is personal, with varied weather perceptions among individuals due to differences in body mass, stature, and physical activity. One must note that being under the direct sun can escalate the heat's effects, with the heat index possibly rising by 15 Fahrenheit (8 Celsius) degrees. Heat index values hold great significance to children. Young individuals usually face greater risks than adults as their sweat production is less. Also, their larger skin surface relative to their small bodies and the high heat generation due to their activity contributes to their vulnerability.
Humans rely on perspiration as a cooling mechanism, wherein the evaporating sweat counteracts excessive warmth. Heightened relative humidity interferes with the body's usual cooling mechanism by reducing evaporation, subsequently decreasing the body's cooling rate and increasing the sensation of heat. As the body gains more heat than it can dissipate, there's a risk of increasing temperatures and resultant overheating.

Humidity

With an average relative humidity of 82%, July is the most humid month.

Rainfall

In Chesterfield, during July, the rain falls for 15.3 days and regularly aggregates up to 2.17" (55mm) of precipitation. In Chesterfield, during the entire year, the rain falls for 138.2 days and collects up to 23.31" (592mm) of precipitation.

Snowfall

April through October are months without snowfall.

Daylight

In July, the average length of the day is 14h and 37min.
On the first day of the month, sunrise is at 5:37 am and sunset at 8:30 pm. On the last day of July, sunrise is at 6:00 am and sunset at 8:12 pm CDT.

Sunshine

In Chesterfield, the average sunshine in July is 10.2h.

UV index

The months with the highest UV index are June through August, with an average maximum UV index of 6. A UV Index reading of 6 to 7 represents a high health risk from unsafe exposure to UV radiation for the ordinary person.
Note: A daily maximum UV index of 6 in July translates into the following instructions:
Endorse precautions and be consistent with sun safety guidelines. Preventing sunburn is paramount. Limit direct sun exposure especially between 10 a.m. and 4 p.m., when UV radiation is at its peak. However, keep in mind that shade structures may not provide full sun protection. By wearing a generously brimmed hat, you can cut UV radiation exposure significantly.
Updated: Jul 26, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What part of the year is the hottest?

The warmest period is July, when temperatures fluctuate between an average high of 83.8°F (28.8°C) and a low of 66.9°F (19.4°C).

Is it hot in Chesterfield during July?

In Chesterfield, 83.8°F (28.8°C) is the average high-temperature and 66.9°F (19.4°C) is the average low-temperature during July. The average heat index (a.k.a. 'apparent temperature', 'real feel'), which factors the actual air temperature with the relative humidity, in July is evaluated at 95°F (35°C).

What is the most humid month?

With an average relative humidity of 82%, July is the most humid month.

What is the average humidity in July?

The average relative humidity in July is 82%.

How many days does it rain in July?

In July, the rain falls for 15.3 days. Throughout July, 2.17" (55mm) of precipitation is accumulated.

When it does not snow?

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

What is the average length of the day in July?

In July, the average day length is 14h and 37min.

When are sunrise and sunset in July?

On the first day of July, sunrise is at 5:37 am and sunset at 8:30 pm. On the last day of the month, sunrise is at 6:00 am and sunset at 8:12 pm CDT.

How long on average sun shines in July?

The average sunshine duration in July in Chesterfield is 10.2h.

When is the highest UV index in Chesterfield?

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

What is the UV index reading in July?

The average daily maximum UV index in July is 6. A UV Index of 6 to 7 symbolizes a high health risk 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 July
Chesterfield, IL

Average temperature in July - Chesterfield, IL
  • Average high temperature in July: 83.8°F

The warmest month (with the highest average high temperature) is July (83.8°F).
The month with the lowest average high temperature is January (34.9°F).

  • Average low temperature in July: 66.9°F

The month with the highest average low temperature is July (66.9°F).
The coldest month (with the lowest average low temperature) is January (22.5°F).

Average pressure in July
Chesterfield, IL

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

The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).

Average wind speed in July
Chesterfield, IL

Average wind speed in July - Chesterfield, IL
  • Average wind speed in July: 5.8mph

The windiest month (with the highest average wind speed) is January (10.1mph).
The calmest month (with the lowest average wind speed) is July (5.8mph).

Average humidity in July
Chesterfield, IL

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

The month with the highest relative humidity is July (82%).
The month with the lowest relative humidity is October (71%).

Average rainfall in July
Chesterfield, IL

Average rainfall in July - Chesterfield, IL
  • Average rainfall in July: 2.17"

The wettest month (with the highest rainfall) is June (3.07").
The driest months (with the least rainfall) are January and February (1.22").

Average rainfall days in July
Chesterfield, IL

Average rainfall days in July - Chesterfield, IL
  • Average rainfall days in July: 15.3 days

The month with the highest number of rainy days is May (17.3 days).
The month with the least rainy days is January (6.3 days).

Average snowfall in July
Chesterfield, IL

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

The month with the highest snowfall is February (2.28").
The months with the least snowfall are April, May, June, July, August, September and October (0").

Average snowfall days in July
Chesterfield, IL

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

The month with the highest number of snowfall days is February (6.3 days).
The months with the least snowfall days are May, June, July, August and September (0 days).

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

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

The month with the longest days is June (Average daylight: 14h and 54min).
The month with the shortest days is December (Average daylight: 9h and 30min).

  • Average sunshine in July: 10h and 1min

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 24min).

Average sunshine days in July
Chesterfield, IL

Average sunshine days in July - Chesterfield, IL
  • Average sunshine days in July: 13 days

The month with the most sunshine days is October (19.8 days).
The month with the least sunshine days is May (11.1 days).

Average UV index in July
Chesterfield, IL

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

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

Average cloud cover in July
Chesterfield, IL

Average cloud cover in July - Chesterfield, IL
  • Average cloud cover in July: 30

The month with the most cloud cover is January (Cloud cover 53).
The months with the least cloud cover are August and September (Cloud cover 29).

Average visibility in July
Chesterfield, IL

Average visibility in July - Chesterfield, IL
  • Average visibility in July: 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).

Chesterfield, Illinois, USA

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