Portland, OR Alder Pollen
Alder pollen in Portland usually peaks around March, reaching High at its worst. Portland's mild, wet climate gives it an early, drawn-out tree season and a famously heavy grass season, fed by the grass-seed farms of the Willamette Valley just to the south.
Alder pollinates as early as February, giving Portland one of the earliest tree seasons in the country.
Alder in Portland today
Monday, July 27, 2026
Alder pollen by month in Portland
How alder usually runs across the year. The current month is outlined.
Managing alder season in Portland
If alder is your trigger, start a daily antihistamine like cetirizine (Zyrtec) or loratadine (Claritin) a week or two before the March peak, rather than waiting for symptoms. Keep windows closed on high-count mornings, shower and change clothes after time outside, and run the AC on recirculate in the car.
When symptoms don't ease with over-the-counter medicine, an allergist in Oregon can test whether alder is really what you react to and talk through longer-term options like allergy shots.
Sources
More pollen in Portland
- Portland grass pollen — peaks June.
- Portland birch pollen — peaks April.
- Portland ragweed pollen — peaks August to September.
- Portland pollen calendar — every allergen, month by month.
- Portland pollen count today — live tree, grass, and weed levels with a 5-day forecast.
- Oregon pollen season — the statewide calendar and other cities.
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Sign up for free alertsSeasonal pattern based on Oregon pollen data and local sources. Today's reading updated daily. MyPollenPal