Southampton is a summer destination. The beach season runs from late June through early September, when the lake is warmest and the town is fully open for business. Canada Day (1 July) weekend and the August long weekend are the busiest times; book accommodation months ahead for those dates.
The shoulder season — late May to mid-June, and September — offers cooler temperatures and quieter beaches, with most restaurants and shops still open. The Chantry Island boat tours run from late May to mid-September. Winter closes most tourism-oriented businesses; the town reverts to a quiet year-round community.