Union, Oregon pollen forecast - today, tomorrow and the week ahead
Pollen Today
Today (20 September) pollen in Union, Oregon is high; ragweed is high; grass and mugwort are moderate.
Pollen Tomorrow
Tomorrow (21 September 2026) grass remains moderate, ragweed remains high, mugwort declining.
7-Day Trend
Over the next week grass, mugwort, and ragweed will decrease.
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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 | 32/100 |
| Willow (Salicaceae) | None | 0/100 |
| Mugwort (Artemisia) | Moderate | 27/100 |
| Ragweed (Ambrosia) | High | 64/100 |
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 | 26/100 | |
| Willow (Salicaceae) | None | 0/100 | — |
| Mugwort (Artemisia) | Low | 22/100 | |
| Ragweed (Ambrosia) | High | 58/100 |
Local Environmental Conditions
Set on a valley farming town in the Grande Ronde Valley of northeastern Oregon, Union's landscape is defined by irrigated hayfields alongside riverside cottonwood and ponderosa pine foothills, the main contributors to seasonal pollen exposure. None of this is unusual for a town with Union's particular mix of terrain and plant life. Allergy sufferers in Union generally plan around this same recurring seasonal rhythm.
In Union, pollen season begins with alder and birch starting in February with maple joining in and continuing through March and April. Grass follows, peaking through May and June, while dock and mugwort keep weed pollen elevated into September. Frequent spring rain across the Pacific Northwest periodically clears pollen from the air, moderating peak counts, a defining feature of the local season.
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Frequently Asked Questions About Pollen in Oregon
Is pollen high in Union, Oregon right now?
On 20 September 2026, overall pollen levels in Union, Oregon are high. Ambrosia is the main contributor to airborne pollen, while artemisia and grass remain at lower levels
Will pollen levels change in Union, Oregon tomorrow?
On 21 September 2026, pollen conditions in Union, Oregon will be different from today, with ambrosia at high levels, grass at moderate levels and artemisia continuing to decline
Is pollen expected to decrease in Union, Oregon this week?
According to the five-day outlook, ambrosia, artemisia, and grass pollen levels are expected to gradually decrease, suggesting improving conditions later in the week.
Which pollen types are currently active in Union, Oregon?
On 20 September 2026, Ambrosia is the dominant pollen source in Union, Oregon. artemisia and grass are also present but at lower levels.
When is pollen season in Union, Oregon?
How often is the Union, Oregon pollen forecast updated?
The Union, Oregon pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in Union, Oregon 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 Union, Oregon 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 Union, Oregon, 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).
