Want to know what the weather is now? O'Fallon, IL - Get the very latest weather forecast, including hour-by-hour views, the 10-day outlook, temperature, humidity, precipitation for your area. Your localized Snow Days weather forecast, from AccuWeather, provides you with the tailored weather forecast that you need to plan your day's activities 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. As of 7:08 pm CDT. Nearby Weather Stations. 7-hour rain and snow forecast for OFallon, IL with 24-hour rain accumulation, radar and satellite maps of precipitation by Weather Underground. No PWS. Get the monthly weather forecast for O'Fallon, IL, including daily high/low, historical averages, to help you plan ahead. Find the most current and reliable 14 day weather forecasts, storm alerts, reports and information for O'Fallon, IL, US with The Weather Network. Weather Underground provides local & long-range weather forecasts, weatherreports, maps & tropical weather conditions for the OFallon area. 66° 93%. Hourly Weather-O'Fallon, IL. Check out the O'Fallon, IL MinuteCast forecast. Plan you week with the help of our 10-day weather forecasts and weekend weather predictions for O'Fallon, Illinois Forecasting the snowfall amount probability, snow accumulation, and a snowfall forecast map. 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 ® Reset Map, or Add PWS. Severe Thunderstorm Warning. Providing you with a hyper-localized, minute-by-minute forecast for the next four hours. Check out our current live radar and weather forecasts for O'Fallon, Illinois to help plan your day O'Fallon, IL Weather History star_ratehome. OFallon Weather Forecasts. Wednesday, April 7. Check out the O'Fallon, IL WinterCast. Location: O'Fallon, IL. 8 pm.