O'Fallon weather
Loading live data…Latest for O'Fallon: NWS (National Blend (NBM)): 80° Partly cloudy · American (NOAA GFS): 78° Partly cloudy · European (ECMWF): 79° Overcast.
The weather map: all three models at once
NWS, American, European side by side around O'Fallon and nearby towns.Live rain radar →Next 14 hours
consensus of the three models7-day forecast
where the models agree, and where they splitO'Fallon, MO is at its warmest in Jul (average highs near 88°F) and coldest in Jan (lows around 27°F), with roughly 45 in of precipitation across the year. Below, compare what NWS, American, European forecast for O'Fallon right now, and see exactly where they disagree.
O'Fallon climate by month
average daytime high and overnight low across a typical yearWhich forecast is most accurate in the US?
CheckWeather Score — graded against the weather that actually happened
The CheckWeather Score blends temperature, wind and rain accuracy — each measured against ERA5 (the recorded weather) over the last 30 days across 40 cities. Lower error means a higher score. The apps you know (AccuWeather, Apple Weather, The Weather Channel) are built on these models.
Common questions
What's the weather in O'Fallon today?
Will it rain in O'Fallon today or tomorrow?
Which forecast is most accurate for O'Fallon?
What is the warmest month in O'Fallon?
How cold does O'Fallon get?
How much rain does O'Fallon get?
The forecasts Americans check
The two biggest apps keep their model a secret, so we can't show their numbers, only link you to them. The National Weather Service is public, so its data sits right in the comparison above.