Except for the Hokkaido area and the subtropical Okinawa region, the weather is mostly temperate, with four seasons. Winters are cool and sunny in the south, cold and sunny around Tokyo (which occasionally has snow), and very cold around Hokkaido, which is covered in snow for up to four months a year. Summer, between June and September, ranges from warm to very hot, while spring and autumn are generally mild throughout the country. Rain falls throughout the year but June and early July is the main rainy season. Hokkaido, however, is much drier than the Tokyo area. Rainfall is intermittent with sunshine. Typhoons are only likely to occur in September or October but rarely last more than a day.

Lightweight cottons and linens are required throughout summer in most areas. Light- to mediumweights during spring and autumn; medium- to heavyweights for winter months, according to region. Much warmer clothes will be needed in the mountains all year round. There is much less rainfall than in Western Europe.

Japan is separated from the Asian mainland by 160km (100 miles) of sea. About 70 per cent of the country is covered by hills and mountains, a number of which are active or dormant volcanoes. A series of mountain ranges runs from northern Hokkaido to southern Kyushu. The Japanese Alps (the most prominent range) run in a north–south direction through central Honshu. The highest mountain is Mount Fuji at 3776m (12,388ft). Lowlands and plains are small and scattered, mostly lying along the coast and composed of alluvial lowlands and diluvial uplands. The coastline is very long in relation to the land area, and has very varied features. The deeply indented bays with good natural harbours tend to be adjacent to mountainous terrain.