O'Fallon, IL Weather - Forecast & Monthly Averages

TEMPERATURE	35
HUMIDITY	66
PRESSURE	103010
WIND COND.	170 14.8

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Weather Quick Facts

The highest monthly average temperature in O'Fallon for July is 77.9 degrees
The lowest monthly average temperature in O'Fallon for January is 31.8 degrees
The most monthly precipitation in O'Fallon occurs in April with 10.2 inches
The air quality index in O'Fallon is 28% worse than the national average
The pollution index in O'Fallon is 122% worse than the national average

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O'Fallon Average Temperature

In the event that the weather data was unavailable for this city, estimates based upon nearby cities were used.
Month	Temp. _(min)	Temp. _(max)	Temp. _(avg)	Precipitation
January	23°F	42°F	32°F	5.6"
February	25°F	45°F	34°F	3.8"
March	37°F	59°F	47°F	7.1"
April	47°F	70°F	57°F	10.2"
May	56°F	77°F	66°F	8.9"
June	65°F	87°F	76°F	9.2"
July	68°F	89°F	78°F	8.0"
August	66°F	88°F	76°F	7.8"
September	58°F	82°F	69°F	8.4"
October	47°F	70°F	57°F	8.6"
November	36°F	57°F	46°F	6.9"
December	28°F	45°F	36°F	8.2"

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O'Fallon air quality index & pollution index

In the event that the air quality/pollution data was unavailable for this city, estimates based upon nearby cities were used.
Index	O'Fallon	Illinois	National
Air quality index	54	41	42
Pollution index	6,055,640	3,148,694	2,726,193

O'Fallon air quality

Measurement	Total
Days measured	365
Days with good air quality	134
Days with moderate air quality	221
Days w/ poor A.Q. for sensitive groups	8
Days with unhealthy air quality	2

Air quality details

Pollutant	Total
Arsenic	0.010%
Benzene	0.070%
Carbon Tetrachloride	0.040%
Lead	0.100%
Mercury	0.230%

Average monthly O'Fallon temperature with heat index

O'Fallon monthly precipitation with daily maximum

O'Fallon monthly snow depth with daily maximum

O'Fallon monthly wind speed information

Nearby cities with good air quality

City	Population	Air Quality Index	National Avg.
Caseyville, IL	4,203	54	8.0%
Washington Park, IL	3,909	54	8.0%
Trenton, IL	2,604	54	8.0%
Shiloh, IL	13,465	54	8.0%
Venice, IL	2,040	54	8.0%
O'Fallon, IL	29,487	54	8.0%

Cities with similar population

City	Population	Air Quality Index	National Avg.
Crofton, MD	29,482	47	6.0%
Austintown, OH	29,467	42	16.0%
Suisun City, CA	29,459	35	30.0%
Canton, GA	29,459	52	4.0%
Seguin, TX	29,458	49	2.0%
O'Fallon, IL	29,487	54	8.0%

Source: The O'Fallon, IL weather data displayed above is derived from the NOAA (National Oceanic and Atmospheric). Air quality and pollution data is derived from the EPA (United States Environmental Protection Agency). Air quality and pollution levels measured in a particular area may not be representative of the entire county.