In most of Japan, the rainy season lasts from the beginning of June to mid July, while it affects the islands of Okinawa about one month earlier. Only Japan's northernmost main island of Hokkaido and the Ogasawara Islands get less affected by the rainy season.

In 2026, Japan's primary rainy season, known as Tsuyu, generally occurs from early June to mid-July. Because Japan is long and narrow, the "rain front" moves from south to north: it begins in Okinawa in early May, reaches Tokyo and Kyoto in early June, and eventually fades out in northern Tohoku by late July. Interestingly, Hokkaido is the only region that effectively escapes Tsuyu, making it a popular refuge for travelers in June. While it doesn't rain every day, the season is characterized by high humidity, overcast skies, and consistent drizzle. Following Tsuyu, Japan enters its typhoon season, which peaks in August and September. During this time, the rain is much more intense but shorter in duration, often accompanied by strong winds. For 2026 travelers, the best "dry" months remain late autumn (October/November) or spring (April), though the rainy season offers the benefit of lush green landscapes and fewer crowds at popular shrines.