Sedalia's calendar revolves around two events. The Scott Joplin International Ragtime Festival runs over five days in early June and is the cultural high point of the year — book accommodation well in advance if you're attending. The Missouri State Fair takes over the south-west side of town for eleven days in mid-August; expect every motel within forty miles to be full and prices to spike.
Outside those windows, late spring (May) and early autumn (September–October) are the most pleasant times to visit. Summer is hot and humid, regularly into the mid-30s Celsius, with thunderstorm risk. Winter is cold but rarely severe; January averages hover around freezing.