Wednesday, April 7. O Fallon past weather with historical weather conditions for the last 30 days, including history of previous high and low temperatures, humidity, dew point, barometric pressure, wind speed, wind direction, wind gust, and rain fall totals for the O Fallon area. 66° 93%. Want to know what the weather is now? Check out our current live radar and weather forecasts for O'Fallon, Illinois to help plan your day O'Fallon, IL - Get the very latest weather forecast, including hour-by-hour views, the 10-day outlook, temperature, humidity, precipitation for your area. 7-hour rain and snow forecast for OFallon, IL with 24-hour rain accumulation, radar and satellite maps of precipitation by Weather Underground. Plan you week with the help of our 10-day weather forecasts and weekend weather predictions for O'Fallon, Illinois As of 7:08 pm CDT. City of O'Fallon, 255 South Lincoln, O'Fallon, IL 62269 Tel: (618) 624-4500 Fax: (618) 624-4508 City Hall Hours: Monday - Friday, 8:00 am - 5:00 pm Website Disclaimer | Government Websites by CivicPlus ® Nearby Weather Stations. Weather Underground provides local & long-range weather forecasts, weatherreports, maps & tropical weather conditions for the OFallon area. Check out the O'Fallon, IL MinuteCast forecast. No PWS. 8 pm. Providing you with a hyper-localized, minute-by-minute forecast for the next four hours. Reset Map, or Add PWS. Location: O'Fallon, IL. Hourly Weather-O'Fallon, IL. O'Fallon, IL Weather History star_ratehome. Check out the O'Fallon, IL WinterCast. Get the monthly weather forecast for O'Fallon, IL, including daily high/low, historical averages, to help you plan ahead. Severe Thunderstorm Warning. Find the most current and reliable 14 day weather forecasts, storm alerts, reports and information for O'Fallon, IL, US with The Weather Network. Forecasting the snowfall amount probability, snow accumulation, and a snowfall forecast map. Your localized Snow Days weather forecast, from AccuWeather, provides you with the tailored weather forecast that you need to plan your day's activities OFallon Weather Forecasts.