July weather forecast
Marietta, IL

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Weather in July

July, like June, in Marietta, Illinois, is another warm summer month, with an average temperature fluctuating between 82.8°F (28.2°C) and 65.8°F (18.8°C).

Temperature

July tends to be the warmest month, with temperatures averaging a daily high of 82.8°F (28.2°C) and a low of 65.8°F (18.8°C).

Heat index

In July, the average heat index is calculated to be a hot 91.4°F (33°C). Ensure additional precautions, heat exhaustion and heat cramps may be expected. Heatstroke could occur from sustained activity.
For clarity, heat index numbers account for light winds and areas under shade. Being exposed to direct sunshine might trigger a heat index increase by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel' or 'apparent temperature', gives a temperature feeling by integrating air temperature and humidity. The impression of weather on a person can be swayed by additional aspects, including metabolic variations, pregnancy, and activity levels. It is essential to realize that direct sunlight can escalate the perceived temperature, increasing the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly important for children. Children frequently do not comprehend the need for rest and hydration. Thirst is an advanced stage of dehydration - staying hydrated, especially during extended physical exercises, is essential.

Humidity

July is the most humid month, with an average relative humidity of 83%.

Rainfall

In Marietta, during July, the rain falls for 15.8 days and regularly aggregates up to 2.17" (55mm) of precipitation. Throughout the year, there are 131.7 rainfall days, and 22.48" (571mm) of precipitation is accumulated.

Snowfall

May through September are months without snowfall in Marietta.

Daylight

In Marietta, the average length of the day in July is 14h and 44min.
On the first day of the month, sunrise is at 5:35 am and sunset at 8:35 pm. On the last day of July, in Marietta, Illinois, sunrise is at 5:58 am and sunset at 8:17 pm CDT.

Sunshine

The months with the most sunshine in Marietta are June and July, with an average of 10.1h of sunshine.

UV index

June through August, with an average maximum UV index of 6, are months with the highest UV index. A UV Index of 6 to 7 symbolizes a high health hazard from exposure to the Sun's UV radiation for the average person.
Note: A typical high UV index of 6 in July suggests the following recommendations:
Undertake precautions and comply with sun safety standards. Protection from skin and eye injury is vital. During the period from 10 a.m. to 4 p.m., UV radiation is highest. Try to avoid direct sunlight during these hours. Boost your sun resistance with garments that are densely woven yet spacious.
Updated: Feb 12, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the hottest time of year in Marietta?

The warmest period in Marietta, Illinois, tends to be July, when average temperatures fluctuate between a high of 82.8°F (28.2°C) and a low of 65.8°F (18.8°C).

How hot is it in Marietta in July?

In Marietta, 82.8°F (28.2°C) is the average high-temperature and 65.8°F (18.8°C) is the average low-temperature during July. The average heat index (a.k.a. 'real feel', 'felt air temperature'), which factors the actual air temperature with the relative humidity, in July is calculated to be 91.4°F (33°C).

What is the most humid month in Marietta?

The most humid month in Marietta is July, with an average relative humidity of 83%.

What is the average humidity in July in Marietta?

In Marietta, the average relative humidity in July is 83%.

How much does it rain in Marietta in July?

In Marietta, Illinois, during July, the rain falls for 15.8 days and regularly aggregates up to 2.17" (55mm) of precipitation.

When it does not snow in Marietta?

In Marietta, snow does not fall in May through September.

How many hours of daylight does Marietta have in July?

The average day length in July in Marietta is 14h and 44min.

What time are sunrise and sunset in July in Marietta?

On the first day of July in Marietta, sunrise is at 5:35 am and sunset at 8:35 pm. On the last day of the month, sunrise is at 5:58 am and sunset at 8:17 pm CDT.

What are the months with the most sunshine in Marietta?

The months with the most sunshine are June and July, with an average of 10.1h of sunshine.

How long on average sun shines in July in Marietta?

In Marietta, the average sunshine duration in July is 10.1h.

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

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

How high is the UV index in July in Marietta?

In Marietta, the average daily maximum UV index in July is 6. A UV Index estimate of 6 to 7 represents 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
Marietta, IL

Average temperature in July - Marietta, IL
  • Average high temperature in July: 82.8°F

The warmest month (with the highest average high temperature) is July (82.8°F).
The month with the lowest average high temperature is January (31.5°F).

  • Average low temperature in July: 65.8°F

The month with the highest average low temperature is July (65.8°F).
The coldest month (with the lowest average low temperature) is January (19.4°F).

Average pressure in July
Marietta, IL

Average pressure in July - Marietta, IL
  • Average pressure in July: 29.96"Hg

The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).

Average wind speed in July
Marietta, IL

Average wind speed in July - Marietta, IL
  • Average wind speed in July: 6.5mph

The windiest month (with the highest average wind speed) is April (10.4mph).
The calmest months (with the lowest average wind speed) are July and August (6.5mph).

Average humidity in July
Marietta, IL

Average humidity in July - Marietta, IL
  • Average humidity in July: 83%

The month with the highest relative humidity is July (83%).
The month with the lowest relative humidity is October (71%).

Average rainfall in July
Marietta, IL

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

The wettest month (with the highest rainfall) is May (3.23").
The driest month (with the least rainfall) is December (0.94").

Average rainfall days in July
Marietta, IL

Average rainfall days in July - Marietta, IL
  • Average rainfall days in July: 15.8 days

The month with the highest number of rainy days is May (16.7 days).
The month with the least rainy days is February (4.7 days).

Average snowfall in July
Marietta, IL

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

The month with the highest snowfall is January (3.35").
The months with the least snowfall are May, June, July, August and September (0").

Average snowfall days in July
Marietta, IL

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

The month with the highest number of snowfall days is January (9.4 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
Marietta, IL

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

The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 18min).

  • Average sunshine in July: 10h and 1min

The months with the most sunshine are June and July (Average sunshine: 10h and 6min).
The month with the least sunshine is January (Average sunshine: 4h and 6min).

Average sunshine days in July
Marietta, IL

Average sunshine days in July - Marietta, IL
  • Average sunshine days in July: 11.7 days

The month with the most sunshine days is December (20.4 days).
The month with the least sunshine days is June (11.1 days).

Average UV index in July
Marietta, IL

Average UV index in July - Marietta, 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
Marietta, IL

Average cloud cover in July - Marietta, IL
  • Average cloud cover in July: 31

The month with the most cloud cover is January (Cloud cover 56).
The month with the least cloud cover is September (Cloud cover 29).

Average visibility in July
Marietta, IL

Average visibility in July - Marietta, 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).

Marietta, Illinois, USA

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