The climate of Japan is predominantly temperate, but varies greatly from north to south. Japan's geographical features divide it into six principal climatic zones:

- Hokkaid?: The northernmost zone has a temperate climate with long, cold winters and cool summers. Precipitation is not heavy, but the islands usually develop deep snow banks in the winter.
- Sea of Japan: On Honsh?'s west coast, the northwest wind in the wintertime brings heavy snowfall. In the summer, the region is cooler than the Pacific area, though it sometimes experiences extremely hot temperatures, because of the foehn wind phenomenon.
- Central Highland: A typical inland climate, with large temperature differences between summer and winter, and between day and night. Precipitation is light.
- Seto Inland Sea: The mountains of the Ch?goku and Shikoku regions shelter the region from the seasonal winds, bringing mild weather throughout the year.
- Pacific Ocean: The east coast experiences cold winters with little snowfall and hot, humid summers because of the southeast seasonal wind.
- Ryukyu Islands: The Ryukyu Islands have a subtropical climate, with warm winters and hot summers. Precipitation is very heavy, especially during the rainy season. Typhoons are common.

The highest temperature ever measured in Japan?40.9 ?C (105.6 ?F)?was recorded on August 16, 2007.

The main rainy season begins in early May in Okinawa, and the stationary rain front responsible for this gradually works its way north until it dissipates in northern Japan before reaching Hokkaid? in late July. In most of Honsh?, the rainy season begins before the middle of June and lasts about six weeks. In late summer and early autumn, typhoons often bring heavy rain.

Japan is home to nine forest ecoregions which reflect the climate and geography of the islands. They range from subtropical moist broadleaf forests in the Ry?ky? and Bonin islands, to temperate broadleaf and mixed forests in the mild climate regions of the main islands, to temperate coniferous forests in the cold, winter portions of the northern islands.