Zhangye Danxia in May

May through September offers the best weather, though July and August bring crowds and heat. Early morning and late afternoon provide the most dramatic lighting — the colors literally change as shadows move across the formations. September hits the sweet spot with mild temperatures and fewer tour groups. Winter visits are possible but cold, with some platforms occasionally closed due to ice. Avoid Chinese national holidays when the park fills with domestic tourists. The best light happens 2 hours before sunset, so plan accordingly. Rain actually enhances the colors temporarily, making the reds more vivid.