Sun Valley pollen forecast - today, tomorrow and the week ahead
Pollen Today
Today (20 September) pollen in Sun Valley is high; ragweed is high; mugwort is moderate.
Pollen Tomorrow
Tomorrow (21 September 2026) ragweed remains high, mugwort declining.
7-Day Trend
Over the next week mugwort and ragweed will decrease; grass will remain stable.
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Features and forecast availability vary by region.
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) | Moderate | 27/100 |
| Ragweed (Ambrosia) | High | 59/100 |
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) | Low | 22/100 | |
| Ragweed (Ambrosia) | High | 53/100 |
Local Environmental Conditions
Sun Valley sits on a mountain valley in the Sawtooth foothills, where the dominant vegetation is a mix of Douglas fir and aspen groves, sagebrush steppe, and mountain wildflower meadows, shaping the local pollen profile across the seasons. Local parks and open ground tend to see higher pollen counts than the denser urban core. Microclimates within the area can shift the timing slightly from one neighborhood to the next.
In Sun Valley, pollen season begins with juniper and cottonwood starting in March before ash peaks during April. Grass follows, peaking through May and June, while grass and sagebrush extend exposure into September. The semi-arid high-elevation climate means fewer rainfall interruptions than in wetter US regions throughout the year.
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Resource Hub
Sports venues in Sun Valley 1 sports venue
Frequently Asked Questions About Pollen in Idaho
Is pollen high in Sun Valley right now?
On 20 September 2026, overall pollen levels in Sun Valley are high. Ambrosia is the main contributor to airborne pollen, while artemisia remain at lower levels
Will pollen levels change in Sun Valley tomorrow?
On 21 September 2026, pollen conditions in Sun Valley will be different from today, with ambrosia at high levels and artemisia continuing to decline
Is pollen expected to decrease in Sun Valley this week?
According to the five-day outlook, ambrosia and artemisia pollen levels are expected to gradually decrease, suggesting improving conditions later in the week.
Which pollen types are currently active in Sun Valley?
On 20 September 2026, Ambrosia is the dominant pollen source in Sun Valley. artemisia are also present but at lower levels. grass are not currently active.
When is pollen season in Sun Valley?
How often is the Sun Valley pollen forecast updated?
The Sun Valley pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in Sun Valley 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 Sun Valley 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 Sun Valley, 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).
