Pollen Count & Forecast for Chicago

Chicago’s spring allergy season (March-May) is dominated by Maple (Acer) and Oak (Quercus) pollen; Ash (Fraxinus) prolific in Lincoln Park and Jackson Park; Elm (Ulmus) widespread across city streets. Ragweed (Ambrosia) contributes significantly from vacant urban lots and riverbanks. Summer (June-August) sees high Grass (Poaceae) pollen levels, originating from the Lake Michigan shoreline and along Chicago River banks.

Lake breezes and the urban grid can trap pollen, leading to localised high concentrations. Autumn and winter see elevated Mould (Alternaria, Cladosporium) spore counts, from damp leaf litter in Cook County Forest Preserves and urban drainage areas.