Bar Harbor pollen forecast - today, tomorrow and the week ahead
Pollen Today
Today (20 September) pollen in Bar Harbor is moderate; ragweed is moderate; grass and mugwort are low.
Pollen Tomorrow
Tomorrow (21 September 2026) levels are similar to today.
7-Day Trend
Over the next week grass, mugwort, 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) | Low | 7/100 |
| Willow (Salicaceae) | None | 0/100 |
| Mugwort (Artemisia) | Low | 10/100 |
| Ragweed (Ambrosia) | Moderate | 47/100 |
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 | 9/100 | |
| Willow (Salicaceae) | None | 0/100 | — |
| Mugwort (Artemisia) | Low | 13/100 | |
| Ragweed (Ambrosia) | Moderate | 49/100 |
Local Environmental Conditions
Set on the granite coast of Mount Desert Island, Bar Harbor's landscape is defined by red spruce and balsam fir alongside coastal blueberry barrens and pitch pine on the ledges, the main contributors to seasonal pollen exposure. Wind patterns across the area help determine how far pollen travels from these source plants. As with most of the region, counts tend to build gradually rather than spike overnight.
Bar Harbor's pollen season opens with maple and elm from March with birch and oak joining in and continuing through April and May. Grass pollen then peaks through June and July, and mugwort and nettle extend exposure into September. A relatively short growing season compresses tree, grass, and weed pollen into a more intense stretch.
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Resource Hub
Pollen forecast neighborhoods 3 neighborhoods
Frequently Asked Questions About Pollen in Maine
Is pollen high in Bar Harbor right now?
On 20 September 2026, overall pollen levels in Bar Harbor are moderate. Ambrosia is the main contributor to airborne pollen, while artemisia and grass remain at lower levels
Will pollen levels change in Bar Harbor tomorrow?
On 21 September 2026, pollen conditions in Bar Harbor will be similar to today, with artemisia at low levels, grass at low levels, ambrosia at moderate levels
Is pollen expected to decrease in Bar Harbor this week?
According to the five-day outlook, artemisia, grass, and ambrosia pollen levels are expected to gradually decrease, suggesting improving conditions later in the week.
Which pollen types are currently active in Bar Harbor?
On 20 September 2026, Ambrosia is the dominant pollen source in Bar Harbor. artemisia and grass are also present but at lower levels.
When is pollen season in Bar Harbor?
How often is the Bar Harbor pollen forecast updated?
The Bar Harbor pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in Bar Harbor 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 Bar Harbor 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 Bar Harbor, 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).
