The park is open year-round, but the best conditions are May through October. Summer weekends bring large crowds; a weekday visit in May or September offers the same views with considerably more room on the walkways. Avoid the hottest part of summer days (midday in July and August) when the light is flat and the heat intense.
Late afternoon is consistently the best time: the sun is low, the colours saturate, and the shadows cut across the ridges to reveal the three-dimensional structure of the formations. Sunrise at Platform 1 is worth the early start for a different quality of light. Winter visits are possible — the park stays open and the crowds are minimal — but the roads to the park can ice over and some shuttle bus routes may run reduced schedules.