The pollen count in Reno peaks in April–September, though allergy sufferers can experience symptoms from as early as early spring. Despite low humidity, the Southwest sees heavy pollen from mulberry, olive, and native desert plants.
The primary driver is Sagebrush — sagebrush is the dominant fall allergen across mountain and desert states. On warm, dry, and windy days the pollen count in Reno can spike dramatically, while rain temporarily brings it down.
Tree pollen starts in early spring and runs through spring. Grass pollen peaks during late spring through early summer. Ragweed dominates from August through October.