July weather forecast
O'Fallon, MO

Weather in July

July in O'Fallon, Missouri, is a tropical summer month, with an average temperature varying between 87.1°F (30.6°C) and 68.5°F (20.3°C).

Temperature

The warmest month is July, with an average high-temperature of 87.1°F (30.6°C) and an average low-temperature of 68.5°F (20.3°C).

Heat index

In July, the average heat index is estimated at a very hot 101.5°F (38.6°C). Take extra precautions, as heat cramps and heat exhaustion are possible. Sustained activity may result in heatstroke.
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 'apparent temperature', 'felt air temperature', 'real feel', or 'feels like', is a measure of how hot it feels when the actual air humidity is factored in. This effect is individual, with diverse people perceiving weather differently for numerous reasons (differences in body mass, height, and shape, metabolic differences, clothing), and activity. Be aware that direct exposure to sunlight increases heat impact and may raise the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially crucial for babies and toddlers. 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.
The human body normally cools itself by perspiration, as evaporated sweat carries heat away from the body. High relative humidity reduces the evaporation rate, resulting in a lower heat removal rate from the body, causing the perception of being overheated. When heat gain surpasses the level the body can shed, body temperature begins to increase, and consequently, overheating and dehydration can occur, with varying severity.

Humidity

In O'Fallon, the average relative humidity in July is 77%.

Rainfall

In O'Fallon, during July, the rain falls for 15.2 days and regularly aggregates up to 2.48" (63mm) of precipitation. Throughout the year, in O'Fallon, there are 132.3 rainfall days, and 21.06" (535mm) of precipitation is accumulated.

Snowfall

In O'Fallon, snow does not fall in April through October.

Daylight

The average length of the day in July in O'Fallon is 14h and 34min.
On the first day of July, sunrise is at 5:41 am and sunset at 8:31 pm. On the last day of the month, sunrise is at 6:03 am and sunset at 8:15 pm CDT.

Sunshine

The average sunshine in July in O'Fallon is 10.4h.

UV index

The months with the highest UV index in O'Fallon are May through August, with an average maximum UV index of 6. A UV Index reading of 6 to 7 represents a high health hazard from exposure to the Sun's UV radiation for the ordinary person.
Note: The daily maximum UV index of 6 in July interpret into the following advice:
Take precautions against overexposure. Protection against sun damage is needed. 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 the 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.
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FAQ

What is the warmest month in O'Fallon?

With an average high-temperature of 87.1°F (30.6°C) and an average low-temperature of 68.5°F (20.3°C), July is the warmest month in O'Fallon, Missouri.

What is the temperature in July in O'Fallon?

The average high-temperature, in July, is 87.1°F (30.6°C), while the average low-temperature is 68.5°F (20.3°C). The average heat index (a.k.a. 'real feel', 'felt air temperature'), which calculates the temperature value influenced by the moisture in the air, in July is estimated at 101.5°F (38.6°C).

What is the average humidity in July in O'Fallon?

The average relative humidity in July in O'Fallon is 77%.

How many days does it rain in July in O'Fallon?

In O'Fallon, in July, it is raining for 15.2 days, with typically 2.48" (63mm) of accumulated precipitation.

When it does not snow in O'Fallon?

April through October are months without snowfall in O'Fallon, Missouri.

What is the average length of the day in July in O'Fallon?

The average day length in July in O'Fallon is 14h and 34min.

When is the sunrise / sunset in July in O'Fallon?

In July, on the first day of the month, sunrise is at 5:41 am and sunset at 8:31 pm. On the last day of the month, in O'Fallon, sunrise is at 6:03 am and sunset at 8:15 pm CDT.

How long on average sun shines in July in O'Fallon?

In July, the average sunshine duration in O'Fallon, Missouri, is 10.4h.

When is the highest UV index in O'Fallon?

May through August, with an average maximum UV index of 6, are months with the highest UV index in O'Fallon, Missouri.

What is the UV index intensity in July in O'Fallon?

In July, the average daily maximum UV index in O'Fallon is 6. A UV Index value of 6 to 7 symbolizes a high hazard to health from exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in July
O'Fallon, MO

Average temperature in July - O
  • Average high temperature in July: 87.1°F

The warmest month (with the highest average high temperature) is July (87.1°F).
The month with the lowest average high temperature is January (37.4°F).

  • Average low temperature in July: 68.5°F

The month with the highest average low temperature is July (68.5°F).
The coldest month (with the lowest average low temperature) is January (23.7°F).

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Average pressure in July
O'Fallon, MO

Average pressure in July - O
  • Average pressure in July: 29.97"Hg

The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).

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Average wind speed in July
O'Fallon, MO

Average wind speed in July - O
  • Average wind speed in July: 5.5mph

The windiest month (with the highest average wind speed) is January (9.1mph).
The calmest month (with the lowest average wind speed) is July (5.5mph).

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Average humidity in July
O'Fallon, MO

Average humidity in July - O
  • Average humidity in July: 77%

The month with the highest relative humidity is May (79%).
The month with the lowest relative humidity is October (70%).

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Average rainfall in July
O'Fallon, MO

Average rainfall in July - O
  • Average rainfall in July: 2.48"

The wettest month (with the highest rainfall) is May (2.76").
The driest month (with the least rainfall) is December (0.91").

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Average rainfall days in July
O'Fallon, MO

Average rainfall days in July - O
  • Average rainfall days in July: 15.2 days

The month with the highest number of rainy days is May (15.7 days).
The month with the least rainy days is February (6.8 days).

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Average snowfall in July
O'Fallon, MO

Average snowfall in July - O
  • Average snowfall in July: 0"

The month with the highest snowfall is February (1.61").
The months with the least snowfall are April, May, June, July, August, September and October (0").

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Average snowfall days in July
O'Fallon, MO

Average snowfall days in July - O
  • Average snowfall days in July: 0 days

The months with the highest number of snowfall days are January and February (5.8 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).

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Average daylight in July /
Average sunshine in July
O'Fallon, MO

Average daylight in July / Average sunshine in July - O
  • Average daylight in July: 14h and 34min

The month with the longest days is June (Average daylight: 14h and 50min).
The month with the shortest days is December (Average daylight: 9h and 30min).

  • Average sunshine in July: 10h and 24min

The month with the most sunshine is June (Average sunshine: 10h and 30min).
The months with the least sunshine are January and February (Average sunshine: 4h and 42min).

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Average sunshine days in July
O'Fallon, MO

Average sunshine days in July - O
  • Average sunshine days in July: 12.6 days

The month with the most sunshine days is December (20.6 days).
The month with the least sunshine days is July (12.6 days).

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Average UV index in July
O'Fallon, MO

Average UV index in July - O
  • Average UV index in July: 6

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

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Average cloud cover in July
O'Fallon, MO

Average cloud cover in July - O
  • Average cloud cover in July: 28

The month with the most cloud cover is January (Cloud cover 50).
The months with the least cloud cover are June, July, August and September (Cloud cover 28).

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Average visibility in July
O'Fallon, MO

Average visibility in July - O
  • 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).

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