Pollen Count & Forecast for Zurich

Zurich’s spring allergy season (March-May) is dominated by Birch and Ash pollen; Birch (Betula) common across the Zurichberg and Adlisberg forests; Ash (Fraxinus) abundant along the Limmat and Sihl riverbanks. Hazel (Corylus) and Alder (Alnus) start early in February. Summer (May-July) has high Grass (Poaceae) pollen levels, originating from Irchelpark and fields near the Uetliberg.

Alpine winds and the basin geography of Lake Zurich trap pollen at low altitudes; the surrounding hills limit air dispersion during calm periods. Autumn and winter see high Mould (Alternaria, Cladosporium) spore counts, from the damp Sihl Forest and decaying leaves in the Platzspitz park.