Spring is the best time to visit Hikone. Cherry blossoms in the castle grounds peak in late March to early April, and evening illuminations are held during the bloom period — the reflection of the lit keep in Genkyu-en's pond is one of the more memorable sights in western Japan. The Japan International Birdman Rally (Birdman Toriningen Contest), where competitors launch home-built gliders from a platform over Lake Biwa, takes place in late August and draws large crowds.
Summer is hot and humid, with July and August temperatures regularly above 32°C. Autumn is cooler and pleasant, with maple colour in the castle grounds peaking in November. Winter is cold — Hikone sits in a basin that channels winds off the Japanese Alps, and snow is more common here than in Kyoto — but the castle looks dramatic against grey skies and crowds thin considerably.