Pollen Count in Spokane, WA

Spokane's semi-arid climate, situated in the Inland Northwest between the Cascades and Rockies, produces a long and often intense allergy season, with dry winds and low humidity helping pollen travel widely across the region.

Tree pollen kicks off the year, typically emerging in late February and peaking from April through May. The dominant offenders include ponderosa pine, birch, alder, cottonwood, maple, elm, ash, and juniper, with birch and cottonwood especially notorious for triggering symptoms.

As trees taper off, grass pollen takes over from late May through July, driven by timothy, orchard grass, Kentucky bluegrass, and ryegrass—many of which grow abundantly across the surrounding Palouse farmland. The overlap between late tree season and early grass season in May often intensifies reactions for multi-sensitive individuals.

Weed pollen dominates from August into October, with sagebrush, Russian thistle (tumbleweed), lamb's quarters, pigweed, and ragweed being the primary culprits, though ragweed levels are generally lower than in the Midwest.

Non-pollen allergens are also significant: dust from agricultural activity, indoor and outdoor molds following wet springs, and seasonal wildfire smoke frequently worsen symptoms.

Overall, Spokane's allergy profile is defined by a lengthy tree-to-weed progression amplified by dry, windy conditions and regional dust and smoke.