The best times to visit Mattsee are during the late spring to early autumn months, specifically from May through September, when the weather is most pleasant for outdoor activities.May and June offer comfortable temperatures, averaging in the high 60s to low 70s Fahrenheit (around 20-23°C), making it ideal for exploring the lake and surrounding nature without the peak summer crowds. These months are great for couples or solo travelers who enjoy hiking, cycling, or simply relaxing by the lake in a more tranquil setting. The Mattsee promenade is particularly pleasant for walks during this time.July and August are the warmest months, with temperatures often reaching the high 70s to low 80s Fahrenheit (around 25-28°C). This period is great for families, as the lake is excellent for swimming, boating, and other water sports. The Strandbad Mattsee, a well-maintained public beach area, offers facilities for a fun day out by the water.September is another excellent month, providing cooler, crisp air and fewer crowds while still offering agreeable temperatures for outdoor pursuits.