Central Honshū's climate varies with its landscape. The best times to visit are generally April, May and late September to early November; temperatures are mild and clear skies prevail. Mid-April is the best time for hanami (cherry-blossom viewing) in the Alps. Expect heavy rains in the tsuyu (monsoon) season, typically a few weeks in June, then sticky summers capped with typhoons as late as October.
Road closures are commonplace in the Alps when the snow sets in from November to March, although higher peaks might remain snowcapped as late as June. Hiking season runs from July to September, until autumn ushers in a brilliant display of kōyō (turning leaves), peaking in mid-October.