O'Fallon, IL Weather Forecast
St. Clair County, Illinois
Live radar, warnings and storm tracking for O'Fallon, with free alerts the moment it counts.
The next few hours
Taller, warmer bars mean heavier rain. Dotted means no reading for that hour.
Hour by hour
Sunrise and sunset
Next five days, scored 0 to 100The first day or two use the HRRR and NBM cloud layers. Later days only have total cloud, so treat them as a rough guide.
Know when sunset at this place will be worth a photo
We score every sunrise and sunset here from the cloud, haze and smoke forecast, and let you know when one is likely to light up. Sunrise the evening before, sunset a few hours ahead.
Seven-day outlook
Free alerts for O'Fallon
Every NWS warning, pushed to your phone, inbox or webhook the moment it is issued.
O'Fallon, IL at a glance
O'Fallon is home to about 31,968 people in St. Clair County, across 16 square miles. It ranks 58th by population of 441 places in Illinois with a forecast here. The nearest neighbour with its own forecast is Shiloh, 3 miles away.
- County
- St. Clair County
- Population
- 31,968 2023 est.
- Land area
- 16 sq mi
- People per sq mi
- 2,024
- Forecast point
- 38.6000°N, 89.9154°W
How well can the network see O'Fallon?
The nearest Doppler radar is KLSX (St. Louis, MO), to the W. Its lowest scan passes about 2,800 ft above O'Fallon. Close enough to see rotation in the low part of a storm, where tornadoes form. O'Fallon is closer to its radar than 53% of US cities.
The closest weather station is KBLV (Belleville/Scott AFB). Representative on most days, though a thunderstorm can hit one and miss the other.
Forecasts near O'Fallon
- Shiloh, IL3 mi
- Fairview Heights, IL5 mi
- Swansea, IL5 mi
- Lebanon, IL6 mi
- Caseyville, IL7 mi
- Belleville, IL7 mi
- Collinsville, IL7 mi
- Mascoutah, IL8 mi
Elsewhere in Illinois
ChicagoAuroraJolietNapervilleRockfordElginAll Illinois forecasts →