Travel
Lake Michigan water temperature: what to expect
Seasonal averages, warmest beaches, and when the lake is swimmable.
5 min read
Lake Michigan is huge and deep enough to stay cool well into summer. The southern end and sheltered bays warm first, while the northern reaches and open water can stay chilly.
Month-by-month
- May: 8–12°C in most of the lake; only the very shallow south warms faster.
- June: 13–18°C; southern beaches are usually swimmable by late June.
- July–August: 20–24°C, peak season; warmest in southern Lake Michigan.
- September: 18–22°C; still swimmable in the south, cooling fast in the north.
- October–April: 6–14°C; not swimmable without a wetsuit or cold-water training.