Spring (April and May) and autumn (September and October) are the best seasons for Tiantai Mountain. The forest is vivid in both, the waterfalls run well in spring after winter rain, and the summit views are clearest in autumn. Summer brings heavy rain and significant humidity, and the mountain can be foggy for days at a time — though the mist through the temple courtyards has its own appeal.
Chinese national holidays in early October (Golden Week) bring heavy domestic crowds to Guoqing Temple. Weekday visits at any time of year are noticeably quieter. Buddhist festivals, particularly Guanyin's birthday in spring, bring organized groups of pilgrims from Japan and Korea, which is interesting to witness but makes the temple very busy.