Mid-June marks the transition to the Pacific Northwest's characteristic dry season, when rain becomes increasingly rare and the region enters its most reliable period of sunny, warm weather. The Pacific High pressure system builds offshore, blocking storm systems and creating stable, dry conditions that typically last through September. Lowland areas may receive less than 2-3 inches of total precipitation from mid-June through September, with some years seeing virtually no measurable rain for months. This dramatic seasonal shift from wet winters to dry summers is a defining feature of the Pacific Northwest's Mediterranean-like climate, creating conditions that support the region's unique mix of temperate rainforest and drought-adapted ecosystems. The dry season triggers important ecological changes including reduced streamflows, increased wildfire risk, and the onset of summer dormancy for many native plants.