When is pollen worst in Green Bay?

Green Bay runs the classic three-wave calendar: tree pollen Apr–Jun, grass Jun–Aug, then ragweed Aug–Oct. The two worst stretches are the spring tree peak and the late-summer ragweed peak. Currently, ragweed pollen is in season.

What's in the air in Green Bay right now?

In September, ragweed pollen is in season in Green Bay, peaking Aug–Oct. On Green Bay's cold-temperate Northeast calendar the typical September level is High, led by ragweed pollen — a seasonal estimate, not a live count.

Is tree or grass pollen higher in Green Bay in spring?

In spring, tree pollen leads in Green Bay — trees pollinate Apr–Jun, ahead of grass (Jun–Aug). 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 Green Bay's pollen season distinctive?

Green Bay sits in the cold-temperate Northeast zone, which means a sharply defined calendar — a hard winter lull, then a compact spring tree burst before grass and a long ragweed fall. That shapes when symptoms hit and which allergen to watch.

How do I reduce pollen exposure in Green Bay?

Through Green Bay's peak windows (tree Apr–Jun, grass Jun–Aug, ragweed Aug–Oct), 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.

When does the next pollen season start in Green Bay?

Tree pollen is next in Green Bay: it opens around week 14 (early April), peaks around week 20, and runs about 91 days.

What is the allergy forecast in Green Bay today?

With no live reading for Green Bay today, its allergy forecast is the seasonal estimate above: a typical September level of High, led by ragweed pollen.

Green Bay, Wisconsin Pollen Count & Allergy Forecast

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

Green Bay, WI · Pollen season

In September, ragweed pollen is in season in Green Bay, peaking Aug–Oct.

Based on the seasonal pollen calendar for this region.

Green Bay on the WeatherStory Allergy Index

Green Bay isn't one of the 100 metros on the WeatherStory Allergy Index, but the nearest ranked metro — Milwaukee, WI, about 100 miles away — sits at #75 with a 244-day combined pollen season.

#75of 100nearest ranked metro

Load index: 30
Combined season: 244 days
Heaviest load: Tree · 91 days
Nearest ranked metro: Milwaukee, WI · ~100 mi

See the full 100 worst U.S. cities for pollen — a modeled seasonal load ranking (see methodology).

Typical now — Septemberseasonal estimate, not a live reading

Ragweed pollen typically leads in Green Bay in September, at an estimated High level.

Pollen by type this season

TreeOut of seasonpeaks Apr–Jun
GrassOut of seasonpeaks Jun–Aug
Weed / RagweedIn seasonpeaks Aug–Oct

What pollinates near Green Bay

The tree, grass, and weed species that drive Green Bay’s pollen seasons, with each plant’s typical peak.

Trees

Oak Quercuspeaks April–May
Birch Betulapeaks April–May
Maple Acerpeaks March–April
Elm Ulmuspeaks March–April
Ash Fraxinuspeaks April–May

Grasses

Timothy Phleum pratensepeaks June–July
Kentucky bluegrass Poa pratensispeaks May–June
Orchard grass Dactylis glomeratapeaks June–July
Perennial ryegrass Lolium perennepeaks June–July

Weeds

Common ragweed Ambrosia artemisiifoliapeaks August–September
Giant ragweed Ambrosia trifidapeaks August–September
Lamb's quarters Chenopodium albumpeaks August–September
Plantain Plantagopeaks June–August

Species are the region’s common wind-pollinated plants; peak months are a seasonal estimate, not a measured count — see methodology.

Green Bay’s allergy year

Typical month-by-month pollen intensity for Green Bay, tuned to its latitude and climate region — darker means higher typical counts. The highlighted column is the current month.

JFMAMJJASOND

TreeApr–Jun

GrassJun–Aug

RagweedAug–Oct

How Green Bay compares to the U.S. average

Each colored bar is Green Bay’s typical season against the national-average window (grey). The offset is the per-city timing shift.

Tree~2 wks later

Grass~2 wks later

Ragweedabout average

“U.S. average” is the textbook tree Mar–May, grass May–Jul, ragweed Aug–Oct calendar. The shift is a phenology estimate (Hopkins’ bioclimatic law), not a measured count — see methodology.

How Green Bay’s pollen count works

The calendar above is tuned to Green Bay’s cold-temperate Northeast climate, not a national average: tree pollen runs from week 14 (early April) to week 26 (late June), grass from week 23 (early June) to week 35 (late August), and ragweed from week 31 (early August) to week 43 (late October) here — a 213-day combined pollen season. Those windows are why ragweed pollen is the one in season in Green Bay right now.

No live count is wired up for Green Bay today, so the seasonal calendar above is your guide to which allergen is in season.

For the science behind Green Bay’s pollen seasons — how counts are measured, when each type peaks, and what the numbers mean — see the pollen count scale and the other pollen & allergy guides.

Frequently asked

When is pollen worst in Green Bay?: Green Bay runs the classic three-wave calendar: tree pollen Apr–Jun, grass Jun–Aug, then ragweed Aug–Oct. The two worst stretches are the spring tree peak and the late-summer ragweed peak. Currently, ragweed pollen is in season.
What's in the air in Green Bay right now?: In September, ragweed pollen is in season in Green Bay, peaking Aug–Oct. On Green Bay's cold-temperate Northeast calendar the typical September level is High, led by ragweed pollen — a seasonal estimate, not a live count.
Is tree or grass pollen higher in Green Bay in spring?: In spring, tree pollen leads in Green Bay — trees pollinate Apr–Jun, ahead of grass (Jun–Aug). 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 Green Bay's pollen season distinctive?: Green Bay sits in the cold-temperate Northeast zone, which means a sharply defined calendar — a hard winter lull, then a compact spring tree burst before grass and a long ragweed fall. That shapes when symptoms hit and which allergen to watch.
How do I reduce pollen exposure in Green Bay?: Through Green Bay's peak windows (tree Apr–Jun, grass Jun–Aug, ragweed Aug–Oct), 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.
When does the next pollen season start in Green Bay?: Tree pollen is next in Green Bay: it opens around week 14 (early April), peaks around week 20, and runs about 91 days.
What is the allergy forecast in Green Bay today?: With no live reading for Green Bay today, its allergy forecast is the seasonal estimate above: a typical September level of High, led by ragweed pollen.