Spring (March–May) and autumn (September–November) are the best times to visit. Temperatures are mild, the lake water is at a comfortable swimming temperature by May, and summer crowds have not yet arrived or have thinned out. Autumn in particular is excellent — warm sunny days, cool nights, and the lake at its clearest.
Summer (June–August) is intense. Temperatures regularly exceed 40°C (104°F), heat radiated off the canyon walls and lake surface makes it hotter still, and the marina is busiest. If you visit in summer, plan water activities for morning and stay off exposed rock in the afternoon. Hydration is serious business — heat illness is a genuine risk.
Winter closes most services at the marina and can bring cold temperatures and occasional snow at the rim level. The lake itself rarely freezes, but the limited facilities make winter visits impractical for most travellers.