Pollen Count & Forecast for Honolulu

Honolulu’s year-round allergy season is dominated by tree and grass pollen; Kiawe (Prosopis pallida) is prolific in dry coastal areas near Diamond Head; Mango (Mangifera indica) and Monkeypod (Samanea saman) produce significant pollen in the Nuʻuanu Valley and Foster Botanical Garden. Guinea Grass (Megathyrsus maximus) contributes significantly along the Koʻolau Range slopes. High Bermuda Grass (Cynodon dactylon) pollen levels occur in Ala Moana Regional Park, originating from turf in Kapiʻolani Park.

Coastal trade winds move allergens offshore; Kona winds reverse this flow and trap particles against mountain ridges. High humidity supports constant Mould (Aspergillus, Penicillium) growth, from damp forest floors in Manoa Valley and organic matter along the Ala Wai Canal.