When is pollen worst in Fairfield?

The late-summer ragweed run is the headline in Fairfield: 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, ragweed pollen is in season.

What's in the air in Fairfield right now?

In September, ragweed pollen is in season in Fairfield, peaking Aug–Nov. On Fairfield's continental Plains 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 Fairfield in spring?

In spring, tree pollen leads in Fairfield — 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 Fairfield's pollen season distinctive?

Fairfield 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 Fairfield?

Through Fairfield'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.

When does the next pollen season start in Fairfield?

Tree pollen is next in Fairfield: it opens around week 10 (early March), peaks around week 15, and runs about 91 days.

What is the allergy forecast in Fairfield today?

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

Fairfield, Iowa Pollen Count & Allergy Forecast

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

Fairfield, IA · Pollen season

In September, ragweed pollen is in season in Fairfield, peaking Aug–Nov.

Based on the seasonal pollen calendar for this region.

Fairfield on the WeatherStory Allergy Index

Fairfield isn't one of the 100 metros on the WeatherStory Allergy Index, but the nearest ranked metro — Des Moines, IA, about 94 miles away — sits at #62 with a 274-day combined pollen season.

#62of 100nearest ranked metro

Load index: 30
Combined season: 274 days
Heaviest load: Ragweed · 122 days
Nearest ranked metro: Des Moines, IA · ~94 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 Fairfield in September, at an estimated High level.

Pollen by type this season

TreeOut of seasonpeaks Mar–May
GrassOut of seasonpeaks May–Jul
Weed / RagweedIn seasonpeaks Aug–Nov

What pollinates near Fairfield

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

Trees

Oak Quercuspeaks April–May
Elm Ulmuspeaks March–April
Cottonwood Populus deltoidespeaks April–May
Hackberry Celtis occidentalispeaks April–May
Ash Fraxinuspeaks April–May

Grasses

Kentucky bluegrass Poa pratensispeaks May–June
Timothy Phleum pratensepeaks June–July
Smooth brome Bromus inermispeaks May–July
Johnson grass Sorghum halepensepeaks June–August

Weeds

Giant ragweed Ambrosia trifidapeaks August–October
Common ragweed Ambrosia artemisiifoliapeaks August–October
Pigweed Amaranthuspeaks August–September
Kochia Bassia scopariapeaks August–September
Lamb's quarters Chenopodium albumpeaks August–September

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

Fairfield’s allergy year

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

JFMAMJJASOND

TreeMar–May

GrassMay–Jul

RagweedAug–Nov

How Fairfield compares to the U.S. average

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

Treeabout average

Grassabout average

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 Fairfield’s pollen count works

The calendar above is tuned to Fairfield’s continental Plains climate, not a national average: tree pollen runs from week 10 (early March) to week 22 (late May), grass from week 18 (early May) to week 30 (late July), and ragweed from week 31 (early August) to week 48 (late November) here — a 274-day combined pollen season. Those windows are why ragweed pollen is the one in season in Fairfield right now.

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

For the science behind Fairfield’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 Fairfield?: The late-summer ragweed run is the headline in Fairfield: 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, ragweed pollen is in season.
What's in the air in Fairfield right now?: In September, ragweed pollen is in season in Fairfield, peaking Aug–Nov. On Fairfield's continental Plains 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 Fairfield in spring?: In spring, tree pollen leads in Fairfield — 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 Fairfield's pollen season distinctive?: Fairfield 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 Fairfield?: Through Fairfield'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.
When does the next pollen season start in Fairfield?: Tree pollen is next in Fairfield: it opens around week 10 (early March), peaks around week 15, and runs about 91 days.
What is the allergy forecast in Fairfield today?: With no live reading for Fairfield today, its allergy forecast is the seasonal estimate above: a typical September level of High, led by ragweed pollen.