Sioux City pollen forecast - today, tomorrow and the week ahead
Pollen Today
Today (20 September) pollen in Sioux City is moderate; ragweed is moderate.
Pollen Tomorrow
Tomorrow (21 September 2026) levels are similar to today.
7-Day Trend
Over the next week grass, mugwort, and ragweed will increase.
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Pollen Risk
Today - 20 September
| Pollen species | Level | Value |
|---|---|---|
| Alder (Alnus) | None | 0/100 |
| Birch (Betula) | None | 0/100 |
| Hazel (Corylus) | None | 0/100 |
| Cypress (Cupressaceae) | None | 0/100 |
| Grass (Poaceae) | None | 0/100 |
| Willow (Salicaceae) | None | 0/100 |
| Mugwort (Artemisia) | None | 0/100 |
| Ragweed (Ambrosia) | Moderate | 33/100 |
Tomorrow - 21 September
| Pollen species | Level | Value | 7-Day Trend |
|---|---|---|---|
| Alder (Alnus) | None | 0/100 | — |
| Birch (Betula) | None | 0/100 | — |
| Hazel (Corylus) | None | 0/100 | — |
| Cypress (Cupressaceae) | None | 0/100 | — |
| Grass (Poaceae) | None | 0/100 | |
| Willow (Salicaceae) | None | 0/100 | — |
| Mugwort (Artemisia) | None | 0/100 | |
| Ragweed (Ambrosia) | Moderate | 31/100 |
Local Environmental Conditions
Sioux City's parks, including Stone State Park and the Missouri River corridor, feature oak, elm, and cottonwood as the main tree pollen sources, with exposure varying between these green areas and the more built-up city centre. Surrounding Iowa, Nebraska, and South Dakota farmland and prairie contribute substantial grass and crop pollen, while the Missouri River valley channels airflows and concentrates pollen across the city.
Sioux City's pollen season opens with maple and elm from late February, followed by oak and cottonwood through April and May. Grass pollen peaks through June and July, with ragweed extending the season strongly into October. The Missouri River valley channels airflows and concentrates pollen, while surrounding Iowa, Nebraska, and South Dakota farmland and prairie contribute substantial grass and crop pollen under prevailing westerly winds.
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Pollen forecast neighborhoods 1 neighborhood
Frequently Asked Questions About Pollen in Iowa
Is pollen high in Sioux City right now?
On 20 September 2026, overall pollen levels in Sioux City are moderate. Ambrosia is the main contributor to airborne pollen
Will pollen levels change in Sioux City tomorrow?
On 21 September 2026, pollen conditions in Sioux City will be similar to today, with ambrosia at moderate levels
Is pollen expected to decrease in Sioux City this week?
According to the five-day outlook, ambrosia, artemisia, and grass pollen levels will increase later in the week.
Which pollen types are currently active in Sioux City?
On 20 September 2026, Ambrosia is the dominant pollen source in Sioux City. artemisia and grass are not currently active.
When is pollen season in Sioux City?
How often is the Sioux City pollen forecast updated?
The Sioux City pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in Sioux City come from nearby or far away?
Studies show that most pollen exposure (often 70–90%) comes from nearby sources, such as local trees and vegetation. A good pollen forecast therefore depends on accurately representing local vegetation. Pollen can travel long distances, but this usually matters only early in the season or during specific wind events.
Are pollen levels in Sioux City based on measurements or forecasts?
Pollen data is often misunderstood. Most "pollen levels" are not real-time measurements, but forecasts.
Direct pollen measurements are typically delayed by 1-2 days because they require manual analysis. To show current conditions in Sioux City, modern forecasts combine recent measurements, weather data, and information about local vegetation.
This allows us to estimate pollen levels for today and the coming days, not just report the past.
Airmine’s atmospheric monitoring platform was developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team, using satellite and Earth observation technologies to improve emissions monitoring.
Understanding the Scale
The 0–100 scores represent risk levels, not direct measurements of pollen or air pollutant concentrations. Higher scores indicate higher risk. Pollen and air quality use different thresholds.
Pollen
| None | 0 | No or negligible risk of exposure. Pollen/mold exposure is expected to be minimal. |
| Low | 0-25 | Low risk of exposure. Small amounts of pollen or mold spores may be present. |
| Moderate | 25-50 | Moderate risk of exposure. Pollen/mold exposure is expected to be noticeable. |
| High | 50-75 | High risk of exposure. Elevated pollen/mold exposure is expected. |
| Very High | 75-100 | Very high risk of exposure. Pollen/mold exposure is expected to be at or near its highest levels. |
Get More in the Airmine Pollen app
Get 15-day pollen forecasts with morning, afternoon and evening detail, plus 5-day air quality forecasts. Explore interactive pollen risk maps, estimated pollen season start, route profiles and a symptoms diary.
Features and forecast availability vary by region. Currently covering Europe, the contiguous US, southern Canada, South Africa, Australia, Indonesia (Java & Bali), Brazil, Paraguay, Uruguay and the Buenos Aires area.
Developed with support from the European Space Agency (ESA) Business Applications and Space Solutions (BASS).
