When is pollen worst in Sioux Falls?

The late-summer ragweed run is the headline in Sioux Falls: 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 what's driving counts this month.

What's in the air in Sioux Falls right now?

In August, ragweed pollen is in season in Sioux Falls — 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 Sioux Falls's continental Plains climate.

Is tree or grass pollen higher in Sioux Falls in spring?

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

Sioux Falls 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 Sioux Falls?

Through Sioux Falls'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.

What is the allergy forecast in Sioux Falls today?

The allergy forecast is the airborne-pollen outlook that drives hay fever — exactly what this page tracks. Today's pollen level for Sioux Falls is shown above, broken into the tree, grass, and ragweed pollen behind most seasonal allergies. When the reading is High or Very High, plan for symptoms and pre-medicate; the seasonal calendar below shows which allergen leads in each part of the year.

Sioux Falls, South Dakota Pollen Count & Allergy Forecast

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

Sioux Falls, SD · Pollen season

In August, ragweed pollen is in season in Sioux Falls — the dominant allergen you're likely reacting to right now.

Based on the seasonal pollen calendar for this region.

Sioux Falls on the WeatherStory Allergy Index

Sioux Falls isn't one of the 100 metros on the WeatherStory Allergy Index, but the nearest ranked metro — Omaha, NE, about 161 miles away — sits at #68 with a 274-day combined pollen season.

#68of 100nearest ranked metro

Load index: 36
Combined season: 274 days
Heaviest load: Tree · 122 days
Nearest ranked metro: Omaha, NE · ~161 mi

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

Typical now — Augustseasonal estimate, not a live reading

Ragweed pollen typically leads in Sioux Falls this time of year, at an estimated Moderate level. No live count is wired up; this reflects the seasonal calendar.

Pollen by type this season

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

What pollinates near Sioux Falls

The tree, grass, and weed species that drive Sioux Falls’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.

Sioux Falls’s allergy year

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

JFMAMJJASOND

TreeMar–Jun

GrassMay–Aug

RagweedAug–Nov

How Sioux Falls compares to the U.S. average

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

Tree~3 wks later

Grass~3 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 Sioux Falls’s pollen count works

The calendar above is tuned to Sioux Falls’s continental Plains climate, not a national average: tree pollen runs from week 10 (early March) to week 23 (early June), grass from week 18 (early May) to week 31 (early August), and ragweed from week 31 (early August) to week 44 (early November) here — a 274-day combined pollen season. Those windows are why ragweed pollen is the one in season in Sioux Falls right now.

No live count is wired up for Sioux Falls 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 Sioux Falls?: The late-summer ragweed run is the headline in Sioux Falls: 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 what's driving counts this month.
What's in the air in Sioux Falls right now?: In August, ragweed pollen is in season in Sioux Falls — 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 Sioux Falls's continental Plains climate.
Is tree or grass pollen higher in Sioux Falls in spring?: In spring, tree pollen leads in Sioux Falls — 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 Sioux Falls's pollen season distinctive?: Sioux Falls 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 Sioux Falls?: Through Sioux Falls'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.
What is the allergy forecast in Sioux Falls today?: The allergy forecast is the airborne-pollen outlook that drives hay fever — exactly what this page tracks. Today's pollen level for Sioux Falls is shown above, broken into the tree, grass, and ragweed pollen behind most seasonal allergies. When the reading is High or Very High, plan for symptoms and pre-medicate; the seasonal calendar below shows which allergen leads in each part of the year.

Pollen & allergy guides

For the science behind Sioux Falls’s pollen seasons — how counts are measured, when each type peaks, and what the numbers mean — see the pollen & allergy guides.

More for Sioux Falls

See the full Sioux Falls, SD weather forecast — hour-by-hour outlook, NOAA radar, satellite, and air quality.