Lakes set in higher mountain elevations like Lake Como and Maggiore stay cold year-round, reaching around 75°F at most in late summer. The warmer lakes with lower elevations and adjacent mountains like Garda and Trasimeno can get quite comfortable for most, up to 84°F or warmer. Pack a wetsuit to comfortably swim year-round, especially if you have kids. The peak open water swimming season is July and August.