[Vick]

From a 10 year old article

My favorite time to visit Japan is during the winter. January and February are usually sunny, with very little rain. The weather is cool, but nothing like the freezing temperatures that batter the northern U.S. during the same period. The first two weeks of January can be a good time to visit Japan for reasons other than the weather. Americans get over the New Year levity rather quickly and get down to business. However, Japan closes completely from December 28 until January 4. The next 10 days or so are replete with a series of "firsts". Many Japanese attach mystic significance to these events. The first writing of the year, the first phone call, the first visit, and many other events, are observed with great solemnity.

The hanami (flower viewing) season is definitely one of the best times to visit Japan. This coincides with the best time for viewing sakura (cherry blossoms), and occurs at different times based on the climatic conditions of the region. In Tokyo, the cherry blossoms usually bloom in late March or early April.