Summer (June–August) is peak season and Lindau is genuinely busy, but the lake is warm enough to swim in and the terrace cafes and ferries are in full operation. July and August see the most visitors. Spring and early autumn are quieter and often have clearer Alpine views — the mountains across the lake are more reliably visible in May and September than in the heat haze of midsummer. Winter is quiet, and some hotels and restaurants close for the season, but the old town is beautiful in the low light and without the crowds.
Nobel Laureates Meeting: Each summer since 1951, Lindau has hosted the Nobel Laureates Meeting, a gathering of Nobel Prize winners with hundreds of young scientists from around the world. It runs for a week in late June or early July and transforms the mood of the town completely — informal lectures, harbour walks with Nobel winners, evening events. Check the programme if you are visiting at that time.