Spring (March–May) and autumn (September–October) are the best times to visit — temperatures are comfortable for hiking, the crowds are somewhat smaller than in summer, and the light in the canyons is good throughout the day. Summer (June–August) is very hot, with temperatures regularly exceeding 40°C, but this is also when the famous light beams in Upper Antelope Canyon are most dramatic around midday. Monsoon thunderstorms in July and August can cause flash floods — slot canyons like Antelope Canyon drain entire watersheds, and floods can arrive with no warning even when it's sunny at ground level. Tours are cancelled or evacuated when storms are in the area.
Winter (November–February) is the quietest time, with much shorter queues for Antelope Canyon. It can be cold, particularly at night, but daytime temperatures are often perfectly pleasant. The light beams in the canyon are less dramatic in winter due to the lower sun angle.
Book Antelope Canyon tours as far in advance as possible — the guided tours are the only legal way to enter, and popular time slots can sell out weeks or months ahead during peak season.