Charleston, Illinois pollen forecast - today, tomorrow and the week ahead
Pollen Today
Today (20 September) pollen in Charleston, Illinois is moderate; grass and ragweed are moderate; mugwort is low.
Pollen Tomorrow
Tomorrow (21 September 2026) ragweed remains moderate, grass declining, mugwort no longer expected.
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) | Moderate | 28/100 |
| Willow (Salicaceae) | None | 0/100 |
| Mugwort (Artemisia) | Low | 8/100 |
| Ragweed (Ambrosia) | Moderate | 46/100 |
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) | Low | 14/100 | |
| Willow (Salicaceae) | None | 0/100 | — |
| Mugwort (Artemisia) | None | 0/100 | |
| Ragweed (Ambrosia) | Moderate | 30/100 |
Local Environmental Conditions
Charleston sits on flat prairie farmland in east-central Illinois, where the dominant vegetation is a mix of cottonwood windbreaks, farmland crops, and bur oak, shaping the local pollen profile across the seasons. Seasonal timing here follows the broader regional pattern typical of this part of the country. The mix of native and introduced species here is fairly typical for this part of the country.
Charleston sees its pollen season open with maple and elm from March before oak takes over and peaks through April. A grass pollen peak follows through May and June; ragweed extends the season into September. The continental Midwest climate produces a well-defined spring tree peak followed by a strong late-summer ragweed season, a defining feature of the local season.
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Frequently Asked Questions About Pollen in Illinois
Is pollen high in Charleston, Illinois right now?
On 20 September 2026, overall pollen levels in Charleston, Illinois are moderate. Ambrosia is the main contributor to airborne pollen, while grass and artemisia remain at lower levels
Will pollen levels change in Charleston, Illinois tomorrow?
On 21 September 2026, pollen conditions in Charleston, Illinois will be different from today, with ambrosia at moderate levels and grass continuing to decline
Is pollen expected to decrease in Charleston, Illinois 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 Charleston, Illinois?
On 20 September 2026, Ambrosia is the dominant pollen source in Charleston, Illinois. grass and artemisia are also present but at lower levels.
When is pollen season in Charleston, Illinois?
How often is the Charleston, Illinois pollen forecast updated?
The Charleston, Illinois pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in Charleston, Illinois 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 Charleston, Illinois 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 Charleston, Illinois, 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).
