Ketchum pollen forecast - today, tomorrow and the week ahead
Pollen Today
Today (20 September) pollen in Ketchum 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
Ketchum's setting on a mountain valley beneath the Sawtooth foothills supports Douglas fir and aspen groves, sagebrush steppe, and mountain wildflower meadows as the leading local vegetation, all factoring into the pollen count through the year. Local parks and open ground tend to see higher pollen counts than the denser urban core. Small local variations aside, this pattern holds fairly steady from year to year.
Ketchum sees its pollen season open with juniper and cottonwood from March with ash joining in and continuing through April. Grass pollen then peaks through May and June, and grass and sagebrush extend exposure into September. Low humidity and high elevation mean pollen disperses easily once released, shaping conditions across the city.
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Frequently Asked Questions About Pollen in Idaho
Is pollen high in Ketchum right now?
On 20 September 2026, overall pollen levels in Ketchum are high. Ambrosia is the main contributor to airborne pollen, while artemisia remain at lower levels
Will pollen levels change in Ketchum tomorrow?
On 21 September 2026, pollen conditions in Ketchum will be different from today, with ambrosia at high levels and artemisia continuing to decline
Is pollen expected to decrease in Ketchum 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 Ketchum?
On 20 September 2026, Ambrosia is the dominant pollen source in Ketchum. artemisia are also present but at lower levels. grass are not currently active.
When is pollen season in Ketchum?
How often is the Ketchum pollen forecast updated?
The Ketchum pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in Ketchum 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 Ketchum 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 Ketchum, 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).
