Marietta pollen forecast — Harmar Historic District neighborhood
Pollen Today
Today (20 September) pollen in Harmar Historic District, Marietta is moderate; grass and ragweed are moderate; mugwort is low.
Pollen Tomorrow
Tomorrow (21 September 2026) grass declining, ragweed declining, 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) | Moderate | 31/100 |
| Willow (Salicaceae) | None | 0/100 |
| Mugwort (Artemisia) | Low | 4/100 |
| Ragweed (Ambrosia) | Moderate | 42/100 |
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 | 10/100 | |
| Willow (Salicaceae) | None | 0/100 | — |
| Mugwort (Artemisia) | None | 0/100 | |
| Ragweed (Ambrosia) | Low | 20/100 |
Local Environmental Conditions
Nearby, just 100-200m from here, a stretch of hazel and willow lines the water, feeding some of spring's earliest pollen. Located at around 350m distant, this area has a wooded stretch of oak and birch, with birch responsible for some of the sharpest spring counts. Nearby, as close as 250m from this location, well-kept lawns and ornamental trees in this park add their share of grass and ragweed pollen.
Water-edge hazel and willow are usually the first allergenic trees active here, arriving ahead of the rest of the season, cresting around late winter. The nearby oak and birch stands take the lead as spring progresses, generally peaking somewhere between April and May. Through late spring, grass pollen climbs steadily toward its June peak, and ragweed later takes the lead from mid-August through October.
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Pollen forecast neighborhoods 25 neighborhoods
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Frequently Asked Questions About Pollen in Ohio
Is pollen high in Marietta right now?
On 20 September 2026, overall pollen levels in Marietta are moderate. Ambrosia is the main contributor to airborne pollen, while grass and artemisia remain at lower levels
Will pollen levels change in Marietta tomorrow?
On 21 September 2026, pollen conditions in Marietta will be different from today, with ambrosia, grass continuing to decline
Is pollen expected to decrease in Marietta 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 Marietta?
On 20 September 2026, Ambrosia is the dominant pollen source in Marietta. grass and artemisia are also present but at lower levels.
When is pollen season in Marietta?
How often is the Marietta pollen forecast updated?
The Marietta pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in Marietta 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 Marietta 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 Marietta, 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).
