Williams Pass & OHV Park pollen forecast - today, tomorrow and the week ahead
Pollen Today
Today (20 September) pollen in Williams Pass & OHV Park is low; grass and ragweed are low.
Pollen Tomorrow
Tomorrow (21 September 2026) grass remains low, ragweed 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) | Low | 24/100 |
| Willow (Salicaceae) | None | 0/100 |
| Mugwort (Artemisia) | None | 0/100 |
| Ragweed (Ambrosia) | Low | 23/100 |
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 | 2/100 | |
| Willow (Salicaceae) | None | 0/100 | — |
| Mugwort (Artemisia) | None | 0/100 | |
| Ragweed (Ambrosia) | None | 0/100 |
Local Environmental Conditions
Here, within easy reach, hazel and willow take root along the waterway, both prolific contributors to early pollen counts. This area, just outside the immediate area, has the tree cover here leans heavily on oak and birch, both key drivers of spring pollen. Small shifts in elevation or soil type can move these figures a little either way.
Hazel and willow by the water are typically first out of the gate, arriving ahead of the rest of the season, cresting around late winter. Oak and birch in the woodland come next, through the heart of spring, usually hitting its highest point sometime between mid-April and mid-May. Grass pollen rises through late spring toward a June high point, before ragweed's late-summer surge carries the season into October.
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Frequently Asked Questions About Pollen in Illinois
Is pollen high in Williams Pass & OHV Park right now?
On 20 September 2026, overall pollen levels in Williams Pass & OHV Park are low. Ambrosia is the main contributor to airborne pollen, while grass remain at lower levels
Will pollen levels change in Williams Pass & OHV Park tomorrow?
On 21 September 2026, pollen conditions in Williams Pass & OHV Park will be different from today, with grass at low levels
Is pollen expected to decrease in Williams Pass & OHV Park 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 Williams Pass & OHV Park?
On 20 September 2026, Ambrosia is the dominant pollen source in Williams Pass & OHV Park. grass are also present but at lower levels. artemisia are not currently active.
When is pollen season in Williams Pass & OHV Park?
How often is the Williams Pass & OHV Park pollen forecast updated?
The Williams Pass & OHV Park pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in Williams Pass & OHV Park 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 Williams Pass & OHV Park 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 Williams Pass & OHV Park, 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).
