Pollen Count & Forecast for Denver
About Pollen in Denver
Denver’s spring (March-May) is dominated by Juniper and Cottonwood pollen; Rocky Mountain Juniper (Juniperus scopulorum) abundant in the Front Range foothills; Eastern Cottonwood (Populus deltoides) and Boxelder Maple (Acer negundo) line the South Platte River and Cherry Creek. Summer (June-August) sees high Blue Grama (Bouteloua gracilis) grass pollen levels, originating from the High Line Canal. Autumn (August-October) has Common Ragweed (Ambrosia artemisiifolia) and Sagebrush (Artemisia) from Washington Park and the eastern plains.
Arid air and altitude keep pollen airborne; dry downslope winds transport particles from the mountains into the city. Winter has low counts; autumn brings Mould (Alternaria, Cladosporium) spores from decaying leaves in City Park and near Sloan’s Lake.