Climate of Japan

[1] As Mount Fuji and the Japanese coastal Alps provide a rain shadow, Nagano and Yamanashi Prefectures receive the least precipitation in Honshu, though it still exceeds 900 millimetres (35 in) annually.

The climate from June to September is marked by hot, wet weather brought by tropical airflows from the Pacific Ocean and Southeast Asia.

[1] These air flows are full of moisture and deposit substantial amounts of rain when they reach land.

Between July and October, typhoons, grown from tropical depressions generated near the equator, can attack Japan with furious rainstorms.

In summer, however, sunshine hours are lowest on exposed parts of the Pacific coast where fogs from the Oyashio current create persistent cloud cover similar to that found on the Kuril Islands and Sakhalin.

The high humidity and the maritime influence make temperatures in the 40s rare, with summers dominated by a more stable subtropical monsoon pattern through most of Japan.

Mount Fuji broke the Japanese record lows for each month except January, February, March, and December.