A large part of Japan is located in the northern temperate zone, creating the traditional four seasons.
Summer starts in June and opens with rain in most parts of the country. The rainy season lasts only a few weeks, to give way to the hot and humid weather. Summer can be quite uncomfortable, with the average temperature readings of around 20°C (80°F). Hokkaido and other mountainous parts, however, generally enjoy cooler temperatures.
August marks the end of summer with a typhoon season that usually stretches to September.
Fall has mild, cool weather. The skies are pleasantly blue, creating a striking backdrop for the changing colors of the flowers and leaves. Fall lasts from September to November.
Winter months are a bit complex. When December arrives, the weather becomes generally cold and dry. Snowfalls are common in the mountainous regions and in the areas facing the Sea of Japan and the Pacific Ocean. The southern part of Japan, on the contrary, experiences relatively warm weather. The winter weather lasts until February.
Spring brings a mild weather, painting a clear and beautiful background for the cherry blossoms. Come March, cherry trees bloom splendidly starting in southern island Kyushu and all the way to the north, leaving Japan awash in soft colors.
If weather is a consideration, then the best seasons for a vacation are fall and spring. In any case, however, Japan is a beautiful country to visit any time of the year. Only make sure to take note of the busiest seasons, which can cause accommodation, reservation, and transportation issues. These include New Year (December 27 to January 4), Golden Week (April 29 to May 5), and Obon Festival (mid-August).