Hiking in Daisetsuzan National Park
Winter comes early to Daisetsuzan. While elevation may seem 'low' (at 2000m) compared to mountains in Honshū that top 3000m, conditions are similar. Snow is still common on trails through early July (and snowy gorges are visible year-round). High season is late July to early August, when the alpine flowers bloom. Coloured leaves appear in mid-September and the first snow falls later that month. By October, even the trailheads are snowed under and you'll need winter mountaineering experience and gear.
Staff at the visitor centres in both Asahidake Onsen and Sōunkyō Onsen can give you the latest information on trail and weather conditions, necessary gear, bear sightings etc. This is bear country, so you'll need to take precautions; a bear bell is advised.