Seasons

Japan has four seasons spring, summer, fall and winter, each of them clearly defined with its own features and attractions. Though the beginning of each season or how long it lasts differ slightly in each district, generally spring lasts from March to May, summer from June to August, fall from September to November, and winter from December to February.
Japan has a mild climate, moderately warm and moist in general. But the country goes from sub-arctic to semi-tropical, bearing the hallmarks of the lengthwise land which stretches from north to south. In parts of Hokkaido located on the northern part of Japan, winter temperature sometimes drop down to 20 degrees below zero or more, while in the southern islands of Okinawa, the temperature seldom goes below 15 degrees ( centigrade ) even in the dead of winter.
Japan also has an average rainfall of about 40 to 100 inches anually. This comes from the fact that there are two ocean currents, meeting along the eastern coast of Japan. One is the Japan Current called Kuroshio flowing northward from the South Pacific carrying warm air. The other is called Oyashio, which flows down south from the Bering Sea off the Siberian coast, and through the east coast of Hokkaido, bringing cool air on its cold belt of water. When these two currents meet, the warm air and cold air run into each other and create low atmospheric pressure, which brings fairly high humidity throughout the year.

[The four seasons of Tokyo]

Tokyo lies in a temperate zone and enjoys a relatively mild, comfortable climate throughout the four seasons. The hot, humid summers are marked by periodic typhoons, and the dry winters bring crisp, clear skies.