Pollen Count & Forecast for Philadelphia

Philadelphia’s spring allergy season (March-May) is dominated by Oak (Quercus) and Maple (Acer) pollen; Oak trees are common in Fairmount Park and along the Schuylkill River; Maple species line many residential streets. Birch (Betula) and Sycamore (Platanus occidentalis) contribute to counts from Wissahickon Valley Park. Summer (May-August) has high Grass (Poaceae) pollen levels, originating near the Delaware River and FDR Park.

High humidity and the urban heat island effect trap allergens in Center City. Late summer and autumn see high Ragweed (Ambrosia) counts from vacant lots and riverbanks. Autumn and winter have elevated Mould (Alternaria, Cladosporium) spore levels; these come from decaying leaves in the forests of Pennypack Park and damp river environments.