Portland, Iowa Pollen Count

Portland pollen count and allergy forecast — tree, grass, and ragweed seasons and what’s pollinating now

Portland, IA · Pollen season

In June, grass pollen is in season in Portland — the dominant allergen you're likely reacting to right now.

Based on the seasonal pollen calendar for this region.

Pollen by type this season

Portland pollen calendar

Typical peak months for each pollen type in this climate region. The highlighted column is the current month.

JFMAMJJASOND
TreeMar–May
GrassMay–Jul
WeedAug–Nov

How Portland’s pollen count works

The calendar above is tuned to Portland’s continental Plains climate, not a national average: tree pollen peaks Mar–May, grass May–Jul, and ragweed Aug–Nov here. Those windows are why grass pollen is the one in season in Portland right now.

No live count is wired up for Portland today, so the seasonal calendar above is your guide to which allergen is in season. Counts run highest on warm, dry, windy mornings and drop after rain, which washes pollen out of the air — reported on the None / Low / Moderate / High / Very High scale.

Frequently asked

When is pollen worst in Portland?
The late-summer ragweed run is the headline in Portland: weed pollen peaks Aug–Nov, the longest and most punishing window of the year here. Tree pollen comes first (Mar–May) and grass bridges the gap (May–Jul), but it's the ragweed stretch that floors most sufferers. Currently, grass pollen is what's driving counts this month.
What's in the air in Portland right now?
In June, grass pollen is in season in Portland — the dominant allergen you're likely reacting to right now. A live count, when available, confirms the day's actual reading; this reflects the typical peak windows for Portland's continental Plains climate.
Is tree or grass pollen higher in Portland in spring?
In spring, tree pollen leads in Portland — trees pollinate Mar–May, ahead of grass (May–Jul). The handoff is the tail of the tree window: tree counts taper as grass climbs, so an early-spring flare is more likely tree pollen and a late-spring one more likely grass.
What makes Portland's pollen season distinctive?
Portland sits in the continental Plains zone, which means the country's worst ragweed — the continental Plains run a long, severe late-summer-into-fall weed season on top of the usual tree and grass peaks. That shapes when symptoms hit and which allergen to watch.
How do I reduce pollen exposure in Portland?
Through Portland's peak windows (tree Mar–May, grass May–Jul, ragweed Aug–Nov), keep windows shut and run AC on recirculate; counts run highest on dry, warm, windy mornings, so push outdoor activity to late afternoon or just after rain, which clears pollen from the air. A HEPA purifier indoors, a saline rinse after being outside, showering before bed, and starting antihistamines a week or two before your worst local window all measurably cut symptoms.
What pollen index counts as high?
Pollen is reported on a categorical scale — None, Low, Moderate, High, and Very High. "High" and above means most allergy sufferers notice symptoms even with brief outdoor exposure, and sensitized people should limit time outside and pre-medicate. "Low" to "Moderate" usually only affects highly sensitive individuals.

More for Portland

See the full Portland, IA weather forecast — hour-by-hour outlook, NOAA radar, satellite, and air quality.

Pollen counts nearby in Iowa