Autumn (March to May) and spring (August to October) are the best seasons. Temperatures are comfortable for walking — daytime highs in the 20s, cool nights — and the light in autumn especially is extraordinary: long shadows, warm colours on the rock, clear skies.
Summer (December to February) is harsh. Temperatures above 40°C are common, and the sun on the open ridgelines is punishing. Wildfires are a risk, and some walking tracks close when temperatures are extreme. If you must visit in summer, stick to early-morning gorge walks and be off the ridge before 10am.
Winter (June to July) brings cold nights — sub-zero at altitude — but clear, bracing days. The days are short but fine for walking, and the ranges are often uncrowded.
Rainfall is unreliable. The creeks run when it rains; in dry years they are reduced to pools or sand. The falls and gorges are best visited a week or two after significant rainfall.