Grants Pass pollen forecast - today, tomorrow and the week ahead
Pollen Today
Today (20 September) pollen in Grants Pass is high; ragweed is high; grass is moderate; mugwort is low.
Pollen Tomorrow
Tomorrow (21 September 2026) levels are similar to today.
7-Day Trend
Over the next week grass and ragweed will decrease; mugwort will remain stable.
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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 | 35/100 |
| Willow (Salicaceae) | None | 0/100 |
| Mugwort (Artemisia) | Low | 19/100 |
| Ragweed (Ambrosia) | High | 65/100 |
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) | Moderate | 27/100 | |
| Willow (Salicaceae) | None | 0/100 | — |
| Mugwort (Artemisia) | Low | 12/100 | |
| Ragweed (Ambrosia) | High | 56/100 |
Local Environmental Conditions
The vegetation around Grants Pass, on the Rogue Valley in the Siskiyou Mountains foothills, is dominated by Douglas fir and oak woodland and madrone, with manzanita adding further seasonal pollen exposure. Wind patterns across the area help determine how far pollen travels from these source plants. As with most of the region, counts tend to build gradually rather than spike overnight.
Grants Pass's tree pollen season begins with alder and birch from February then maple follows, running through March and April. Grass pollen rises through May and June, and mugwort and nettle extend exposure into September. The damp, mild regional climate keeps pollen counts lower than in drier parts of the country, though spring rain events can trigger brief spikes, shaping conditions across the city.
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Frequently Asked Questions About Pollen in Oregon
Is pollen high in Grants Pass right now?
On 20 September 2026, overall pollen levels in Grants Pass are high. Ambrosia is the main contributor to airborne pollen, while grass and artemisia remain at lower levels
Will pollen levels change in Grants Pass tomorrow?
On 21 September 2026, pollen conditions in Grants Pass will be similar to today, with ambrosia at high levels, artemisia at low levels, grass at moderate levels
Is pollen expected to decrease in Grants Pass this week?
According to the five-day outlook, ambrosia and grass pollen levels are expected to gradually decrease, suggesting improving conditions later in the week.
Which pollen types are currently active in Grants Pass?
On 20 September 2026, Ambrosia is the dominant pollen source in Grants Pass. grass and artemisia are also present but at lower levels.
When is pollen season in Grants Pass?
How often is the Grants Pass pollen forecast updated?
The Grants Pass pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in Grants Pass 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 Grants Pass 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 Grants Pass, 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).
