Japan is an archipelago consisting of the four major islands of Hokkaido, Honshu, Shikoku and Kyushu and many smaller ones. The climate is mostly temperate but the archipelago covers several climate zones and varies considerably from the sub-tropical island of Okinawa in the far south to the northern island of Hokkaido with long winters and heavy snow. Japan’s climate is influenced by geography, ocean currents and seasonal winds. Even on the main island the climate varies from the western Japan Sea side, which gets cold fronts from Siberia, and the eastern Pacific Ocean coast which gets warmer ocean currents.
Japan has four main seasons with the rainy season (June-July) perhaps its 5th season and the typhoon season (August-October) perhaps the 6th. The seasons don’t pass unnoticed in Japan with each boasting its own popular activities and destinations.
In Spring (春haru) (March, April, May), the temperatures are warm but not hot, winds are calm and there is not too much rain. The famous cherry blossoms（桜の花sakura no hana) start blooming in southern Kyushu at the end of March and sweep across the country to the northeast through April.
Cherry blossom viewing ( 花見hana-mi) is a time of revelry and festivals. Golden week (a group of national holidays at the end of April and beginning of May) is the busiest travel season.
Summer (夏natsu) (June, July, August) begins with the rainy season (梅雨tsuyu) for most of the country (not Hokkaido), which lasts for about 40 days through June to July. Hydrangea (アジサイajisai) blooms turn pale lilac then a deep blue as the rains continue.
The weather turns extreme and oppressive humidity and high temperatures (the mid 30s in mostly but up to 40° in some areas) are ever-present in July and August.
Summer is a time for festivals (まつりmatsuri) and fireworks (はなび hanabi). Obon, the biggest festival of the year, is held in August (July in some areas). Schools are on holiday through July and August.
Autumn (秋aki) (September, October, November) is a wonderful time to be in Japan. Temperatures and humidity drop but it is still warm. The beautiful autumn colours start in the north and higher altitudes and spread to all areas in November with the red leaves of late autumn (こよkoyo). However, typhoons often hit the southern parts of Japan. September is the time for viewing the moon (月見tsukimi). Autumn also brings festivals to many areas. In October there is the major jidai (historical) festival in Kyoto and in November there is the major festival at Asakusa in Tokyo with a huge historical parade.
Winter (冬fuyu) (December, January, February) characteristically brings snow (sometimes very heavy) to the north and much of the Japan Sea coast. The rest of the mainland gets some snow and average temperatures around 1-5° Generally though it remains dry, clear and crisp on the more populated east.
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.
What to wear
- In summer - Light comfortable clothing that dries easily (because of the high humidity) is best. Lightweight cottons and linens are good.
- In spring - Summer clothes in the south and jumpers and jackets further north.
- During spring and autumn - Light to medium weights. Layered clothing is best with jumpers and jackets for the mountainous areas.
- For winter - medium to heavyweights according to region. Winter coats, ski jackets, etc. and good shoes suitable for snow. A rainproof jacket and umbrella is advisable.
- Much warmer clothes will be needed in the mountains all year round.
- Shoes and socks - Since it's a Japanese custom to take off your shoes when you're indoors, you might find yourself taking off your shoes very often. So good socks are advisable (no holes in socks or stockings).