July and August are the only months when climbing is possible. The Yoshida and Subashiri trails open in early July; Fujinomiya and Gotemba follow around 10 July. All four close in mid-September. August is peak season — trails are packed, mountain huts require booking months ahead, and the summit can resemble a slow-moving queue. Weekdays in mid-July or early September are the least crowded times to climb.
October and November offer the best conditions for viewing the mountain without climbing it. The skies are clearer than summer, the maple trees around the Five Lakes turn red, and the mountain is dusted with early snow. This is the most photogenic season.
December to March — the mountain is snow-covered and at its most dramatic from a distance. The skies around Mount Fuji are often clear in winter, giving the sharpest views from the lakes and from trains between Tokyo and Osaka. No climbing, but Fujiyama Ski Resort and a few others operate on the lower slopes.
April and May bring cherry blossoms to the lakes area and the famous combination of pink blossom with the snow-capped cone. The crowds are significant in cherry blossom season. The mountain itself is still snow-covered and inaccessible.