July weather forecast
Potomac, IL

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Weather in July

July, the same as June, is another warm summer month in Potomac, Illinois, with an average temperature varying between 64.4°F (18°C) and 81.1°F (27.3°C).

Temperature

July, with its high-temperature average of 81.1°F (27.3°C) and a low-temperature average of 64.4°F (18°C), is the warmest month.

Heat index

July's mean heat index is calculated to be a hot 87.8°F (31°C). Fatigue might occur with continuous exposure and activity, potentially causing heat cramps.
It is important to note that the heat index values are for shaded areas and light wind scenarios. Uninterrupted exposure to the sun may boost the heat index values by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature' or 'felt air temperature', is a calculated temperature value of how hot it feels when the moisture in the air is factored in. A person's impression of weather can be affected by numerous aspects, among them metabolic variations, pregnancy, and activity levels. Should you be directly under the sun, anticipate a possible increase in the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values hold particular importance for children. Young ones often ignore the need to take a break and drink fluids. Thirst is a late-stage symptom of dehydration - hence, maintaining hydration, particularly during extended physical activities, is crucial.

Humidity

July is the most humid month in Potomac, with an average relative humidity of 85%.

Rainfall

In Potomac, Illinois, in July, during 17.7 rainfall days, 2.13" (54mm) of precipitation is typically accumulated. Throughout the year, there are 146.3 rainfall days, and 22.76" (578mm) of precipitation is accumulated.

Snowfall

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

Daylight

In July, the average length of the day in Potomac is 14h and 43min.
On the first day of July in Potomac, sunrise is at 5:25 am and sunset at 8:24 pm. On the last day of the month, sunrise is at 5:48 am and sunset at 8:06 pm CDT.

Sunshine

In Potomac, the average sunshine in July is 9.9h.

UV index

June through August, with an average maximum UV index of 6, are months with the highest UV index in Potomac, Illinois. A UV Index reading of 6 to 7 represents a high threat to health from exposure to the Sun's UV rays for the ordinary person.
Note: In July, the maximum UV index of 6 suggests these recommendations:
Adhere to precautions and respect sun safety doctrines. Avoiding sunburn is vital. Stay in the shade and avoid direct Sun exposure from 10 a.m. to 4 p.m., a time when UV radiation is at its strongest, and remember that parasols or canopies do not offer full protection. Your best bet for sun defense on the face, eyes, and neck is a hat with a wide brim.
Updated: Feb 12, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the warmest month in Potomac?

Potomac, Illinois, experiences its average highest temperatures in July, reaching a peak of 81.1°F (27.3°C) and a minimum of 64.4°F (18°C).

What is the usual temperature for Potomac in July?

In Potomac, in July, the average high-temperature is 81.1°F (27.3°C), and the average low-temperature is 64.4°F (18°C). The average heat index (a.k.a. 'feels like', 'felt air temperature'), which represents the influence of relative humidity on air temperature, in July is calculated to be 87.8°F (31°C).

What is the most humid month in Potomac?

With an average relative humidity of 85%, July is the most humid month.

What is the average humidity in July in Potomac?

In July, the average relative humidity in Potomac, Illinois, is 85%.

How much does it rain in Potomac in July?

In Potomac, during July, the rain falls for 17.7 days and regularly aggregates up to 2.13" (54mm) of precipitation.

When it does not snow in Potomac?

May through October are months without snowfall in Potomac, Illinois.

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

The average day length in July is 14h and 43min.

When are sunrise and sunset in July in Potomac?

In July, on the first day of the month, sunrise is at 5:25 am and sunset at 8:24 pm. On the last day of the month, sunrise is at 5:48 am and sunset at 8:06 pm CDT.

How many hours of sunshine does Potomac have in July?

The average sunshine duration in July in Potomac, Illinois, is 9.9h.

When is the highest UV index in Potomac?

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

How high is the UV index in July in Potomac?

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

Average temperature in July - Potomac, IL
  • Average high temperature in July: 81.1°F

The warmest month (with the highest average high temperature) is July (81.1°F).
The month with the lowest average high temperature is January (31.5°F).

  • Average low temperature in July: 64.4°F

The month with the highest average low temperature is July (64.4°F).
The coldest month (with the lowest average low temperature) is January (19.8°F).

Average pressure in July
Potomac, IL

Average pressure in July - Potomac, IL
  • Average pressure in July: 29.98"Hg

The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).

Average wind speed in July
Potomac, IL

Average wind speed in July - Potomac, IL
  • Average wind speed in July: 6.3mph

The windiest month (with the highest average wind speed) is January (10.5mph).
The calmest months (with the lowest average wind speed) are July and August (6.3mph).

Average humidity in July
Potomac, IL

Average humidity in July - Potomac, IL
  • Average humidity in July: 85%

The month with the highest relative humidity is July (85%).
The month with the lowest relative humidity is October (72%).

Average rainfall in July
Potomac, IL

Average rainfall in July - Potomac, IL
  • Average rainfall in July: 2.13"

The wettest month (with the highest rainfall) is May (2.76").
The driest month (with the least rainfall) is February (1.18").

Average rainfall days in July
Potomac, IL

Average rainfall days in July - Potomac, IL
  • Average rainfall days in July: 17.7 days

The month with the highest number of rainy days is July (17.7 days).
The month with the least rainy days is February (6.7 days).

Average snowfall in July
Potomac, IL

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

The month with the highest snowfall is February (2.32").
The months with the least snowfall are May, June, July, August, September and October (0").

Average snowfall days in July
Potomac, IL

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

The month with the highest number of snowfall days is January (9.8 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
Potomac, IL

Average daylight in July / Average sunshine in July - Potomac, 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 24min).

  • Average sunshine in July: 9h and 5min

The month with the most sunshine is June (Average sunshine: 10h and 0min).
The month with the least sunshine is January (Average sunshine: 3h and 54min).

Average sunshine days in July
Potomac, IL

Average sunshine days in July - Potomac, IL
  • Average sunshine days in July: 9.5 days

The month with the most sunshine days is November (18.7 days).
The month with the least sunshine days is July (9.5 days).

Average UV index in July
Potomac, IL

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

The months with the highest UV index are June, July and August (UV index 6).
The month with the lowest UV index is December (UV index 1).

Average cloud cover in July
Potomac, IL

Average cloud cover in July - Potomac, IL
  • Average cloud cover in July: 34

The month with the most cloud cover is January (Cloud cover 59).
The months with the least cloud cover are June, August and September (Cloud cover 33).

Average visibility in July
Potomac, IL

Average visibility in July - Potomac, IL
  • Average visibility in July: 5mi

The months with the highest visibility are January, February, March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are July and August (5mi).

Potomac, Illinois, USA

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