Spearfish pollen forecast - today, tomorrow and the week ahead
Pollen Today
Today (20 September) pollen in Spearfish is moderate; ragweed is moderate.
Pollen Tomorrow
Tomorrow (21 September 2026) ragweed increasing, grass at low levels, mugwort at low levels.
7-Day Trend
Over the next week mugwort will increase; grass 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) | None | 0/100 |
| Willow (Salicaceae) | None | 0/100 |
| Mugwort (Artemisia) | None | 0/100 |
| Ragweed (Ambrosia) | Moderate | 31/100 |
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 | 21/100 | |
| Willow (Salicaceae) | None | 0/100 | — |
| Mugwort (Artemisia) | Low | 7/100 | |
| Ragweed (Ambrosia) | High | 54/100 |
Local Environmental Conditions
Spearfish's setting on a canyon-mouth town at the edge of the Black Hills supports ponderosa pine forest, canyon-bottom cottonwood, and mixed-grass prairie as the leading local vegetation, all factoring into the pollen count through the year. This mix of plant life is fairly typical for the wider area around Spearfish. None of this differs sharply from one year to the next barring unusual weather.
The pollen calendar in Spearfish opens with elm and cottonwood starting March then ash builds through April. A grass pollen peak follows through May and June; a strong ragweed peak follows in late summer into September. The continental climate and surrounding farmland drive a well-defined spring tree peak and a strong late-summer ragweed season, shaping conditions across the city.
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Frequently Asked Questions About Pollen in South Dakota
Is pollen high in Spearfish right now?
On 20 September 2026, overall pollen levels in Spearfish are moderate. Ambrosia is the main contributor to airborne pollen
Will pollen levels change in Spearfish tomorrow?
On 21 September 2026, pollen conditions in Spearfish will be different from today, with artemisia at low levels, grass at low levels and ambrosia increasing
Is pollen expected to decrease in Spearfish this week?
According to the five-day outlook, ambrosia and grass pollen levels are expected to gradually decrease, while artemisia pollen will increase, suggesting mixed conditions later in the week.
Which pollen types are currently active in Spearfish?
On 20 September 2026, Ambrosia is the dominant pollen source in Spearfish. artemisia and grass are not currently active.
When is pollen season in Spearfish?
How often is the Spearfish pollen forecast updated?
The Spearfish pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in Spearfish 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 Spearfish 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 Spearfish, 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).
