Kalbarri's climate is semi-arid, with hot dry summers and mild winters. The best time to visit is the Western Australian winter and spring.
Wildflower season (July to October) is Kalbarri's most celebrated period — the surrounding scrubland erupts with everlastings, banksias, kangaroo paws, and hundreds of other species. Western Australia's wildflower season is one of the great natural spectacles of the continent, and the area around Kalbarri is one of the best places to see it. August and September are the peak weeks, with roadside verges, national park areas, and even the town's own gardens covered in colour.
Winter (June to August) brings mild days (15-22°C), comfortable gorge walking temperatures, and reliable whale watching along the coast. Humpback whales begin their northward migration in June and return south in October-November.
Summer (November to March) is hot — temperatures routinely exceed 40°C inland, making the gorge walks impractical between about 10am and 5pm. The coast is somewhat cooler but the UV is extreme. Summer is also cyclone season, with occasional heavy rain and strong winds. If you do visit in summer, start gorge walks before sunrise and retreat to the beach or town by mid-morning.