Pollen Count & Forecast for Porto

Porto’s spring allergy season (February-May) is dominated by Wall Pellitory and Oak pollen; Wall Pellitory (Parietaria judaica) prolific on stone walls in Ribeira and Foz do Douro; Oak (Quercus) widespread in Parque da Cidade and Jardim de Serralves. Birch (Betula) and Olive (Olea europaea) contribute significantly to tree counts. Summer (May-July) has peak Grass (Poaceae) pollen levels, originating from the lawns of the Palácio de Cristal and Douro River banks.

Coastal winds from the Atlantic Ocean carry pollen inland; narrow streets in the historic center trap these particles. Humid maritime air fuels Mould (Alternaria, Cladosporium) growth year-round. Spores increase during wet winters (November-February); levels are high near the riverbanks and in damp stone buildings.