Pollen Count & Forecast for Niigata

Niigata’s spring allergy season (February–May) is dominated by Cedar and Cypress pollen; Japanese Cedar (Cryptomeria japonica) is concentrated on Mount Yahiko and the Kakuda mountains; Japanese Cypress (Chamaecyparis obtusa) is widespread in the hill forests. Alder (Alnus) is common along Shinano River banks. Summer and autumn (August–October) have high Mugwort (Artemisia) and Japanese Hop (Humulus japonicus) levels; these grow along the Agano River and Toyanogata Lagoon.

Sea breezes from the Sea of Japan carry pollen inland; the Echigo Plain traps particles against the eastern mountains. Autumn and winter see elevated Mould (Alternaria, Cladosporium) spore counts, from the humid wetlands of Sakata Lagoon and damp city environments.