Spring (August to October) is the prime season. The wildflowers across the Avon Valley are extraordinary, the days are warm without being hot, and the drive from Perth through the Darling Ranges is at its most rewarding. The Avon Descent, a 124-kilometre white-water race from Northam to Toodyay held each August, is one of Western Australia's great spectator events and fills the town with energy for its duration.
Summer (December to February) can be very hot — temperatures regularly reach 38–40°C and the town is quiet. Autumn is pleasant and less visited, with mild weather and the harvested wheat country taking on golden tones.
The York Flying 50 — a classic car race on the streets of York — has traditionally been held in October and draws enthusiasts from across the state. Check current dates before planning around it, as timing can shift. The York Jazz and Arts Festival runs in September.
Winter days are mild and clear; nights get cold. If you are visiting purely for the architecture and the antique shops, winter is perfectly fine.