Summer is the obvious window. The Cascade Falls lights run nightly from Memorial Day through Labor Day; the Hot Air Jubilee balloon festival fills the sky on the third weekend in July; NASCAR races at the Michigan International Speedway are in June and August.
Autumn is genuinely good for the surrounding lakes country — the maples around the Jackson chain of lakes turn early October. Winters are grey and cold; January and February see lake-effect snow blowing in from the west.