South Bend has a classic Great Lakes climate: cold winters, warm humid summers, and generally pleasant springs and autumns. The most energetic time to visit is during the Notre Dame football season, which runs from September through November — home game weekends transform the city, hotels fill up weeks in advance, and the atmosphere around campus is genuinely electric.
Spring and summer are the best seasons for outdoor activities: the East Race Waterway runs on weekends, Howard Park fills up, and the riverfront trail system is at its most pleasant. Winter is cold and often snowy; the outdoor ice skating ribbon at Howard Park is the bright spot of the colder months. Avoid visiting on Notre Dame home game weekends if you want quieter streets and lower hotel rates, but do visit if you want to experience the spectacle.