Johnstown pollen forecast — Johnstown Flood National Memorial neighborhood
Pollen Today
Today (20 September) pollen in Johnstown Flood National Memorial, Johnstown is moderate; ragweed is moderate; grass and mugwort are low.
Pollen Tomorrow
Tomorrow (21 September 2026) ragweed declining, grass no longer expected, mugwort no longer expected.
7-Day Trend
Over the next week grass, mugwort, and ragweed will increase.
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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) | Low | 21/100 |
| Willow (Salicaceae) | None | 0/100 |
| Mugwort (Artemisia) | Low | 10/100 |
| Ragweed (Ambrosia) | Moderate | 36/100 |
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) | None | 0/100 | |
| Ragweed (Ambrosia) | Low | 5/100 |
Local Environmental Conditions
Johnstown Flood National Memorial, a National Park Service site memorializing the catastrophic 1889 flood, shares its vegetation profile with the broader Johnstown area, so pollen exposure here tracks the same regional sources found across the city. Visitors should expect roughly the same seasonal pattern as elsewhere in the city, with only minor local variation.
Situated a landmark in Johnstown, Johnstown Flood National Memorial shares the area's pollen timeline, beginning with cedar and elm in late February then oak follows, running through April. Grass follows, peaking through May and June, while mugwort and nettle extend exposure into September. Humid summers in the mid-Atlantic favor a longer weed pollen tail into early autumn, a defining feature of the local season.
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Frequently Asked Questions About Pollen in Pennsylvania
Is pollen high in Johnstown right now?
On 20 September 2026, overall pollen levels in Johnstown are moderate. Ambrosia is the main contributor to airborne pollen, while artemisia and grass remain at lower levels
Will pollen levels change in Johnstown tomorrow?
On 21 September 2026, pollen conditions in Johnstown will be different from today, with ambrosia continuing to decline
Is pollen expected to decrease in Johnstown this week?
According to the five-day outlook, ambrosia, artemisia, and grass pollen levels will increase later in the week.
Which pollen types are currently active in Johnstown?
On 20 September 2026, Ambrosia is the dominant pollen source in Johnstown. artemisia and grass are also present but at lower levels.
When is pollen season in Johnstown?
How often is the Johnstown pollen forecast updated?
The Johnstown pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in Johnstown 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 Johnstown 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 Johnstown, 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).
