Lake Winnipesaukee in May

June through September is lake season, but each month feels different. June brings cooler water temperatures — around 65°F — but fewer crowds and lower accommodation prices. July and August are peak season for good reason: water temps hit 75°F, perfect for swimming without a wetsuit. But expect crowds, especially on weekends, and book accommodations months ahead. September might be the sweet spot. The water stays warm from the summer heat, the crowds thin out after Labor Day, and the first hints of fall foliage start showing up in the surrounding hills. October can be stunning for leaf peeping, but most lake activities shut down and water temperatures drop to the 50s. Winter transforms the lake into a different destination entirely — ice fishing, snowmobiling, and cross-country skiing take over, but many restaurants and shops close until spring. Spring is mud season in New Hampshire, meaning unpredictable weather and limited activities until late May.