Thunder Bay Pollen Forecast - Today, Tomorrow and the Week Ahead
Pollen Today
Today (10 October) pollen in Thunder Bay is moderate; mugwort and ragweed are moderate; grass, mold (alternaria), and mold (cladosporium) are low.
Pollen Tomorrow
Tomorrow (11 October 2026) grass remains low, ragweed remains moderate, mold (alternaria) remains low, mold (cladosporium) remains low, mugwort declining.
7-Day Trend
Over the next week grass, mugwort, ragweed, mold (alternaria), and mold (cladosporium) will decrease.
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Pollen Risk
Today - 10 October
| 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 | 25/100 |
| Willow (Salicaceae) | None | 0/100 |
| Mugwort (Artemisia) | Moderate | 26/100 |
| Ragweed (Ambrosia) | Moderate | 33/100 |
| Mold (Alternaria) | Low | 4/100 |
| Mold (Cladosporium) | Low | 13/100 |
Tomorrow - 11 October
| 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 | 20/100 | |
| Willow (Salicaceae) | None | 0/100 | — |
| Mugwort (Artemisia) | Low | 20/100 | |
| Ragweed (Ambrosia) | Moderate | 27/100 | |
| Mold (Alternaria) | Low | 11/100 | |
| Mold (Cladosporium) | Low | 21/100 |
Local Environmental Conditions
Most of the area around Thunder Bay is built-up land, with some woodland. With standing water close by, lakeside trees such as poplar contribute to the local mix. Common allergenic trees nearby include maple, birch and poplar. Grass pollen adds noticeably to the overall load. Locally, street trees, parks and lawns are the main sources in the built-up parts.
Maple, birch and poplar lead the season in mid-spring, bringing the main tree pollen peak. Grasses take over in early summer and keep pollen in the air into late summer. A smaller weed peak follows from midsummer into mid-fall. Spring is the wettest time of year, and heavy showers can bring short breaks in pollen. By late fall, as temperatures fall to around freezing, pollen levels are low again.
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Resource Hub
Pollen forecast neighborhoods 3 neighborhoods
Sports venues in Thunder Bay 1 sports venue
Frequently Asked Questions About Pollen in Ontario
Is pollen high in Thunder Bay right now?
On 10 October 2026, overall pollen levels in Thunder Bay are moderate. Ambrosia is the main contributor to airborne pollen, while artemisia and grass remain at lower levels
Will pollen levels change in Thunder Bay tomorrow?
On 11 October 2026, pollen conditions in Thunder Bay will be different from today, with ambrosia at moderate levels, grass at low levels and artemisia continuing to decline
Is pollen expected to decrease in Thunder Bay this week?
According to the five-day outlook, ambrosia, artemisia, and grass pollen levels are expected to gradually decrease, suggesting improving conditions later in the week.
Which pollen types are currently active in Thunder Bay?
On 10 October 2026, Ambrosia is the dominant pollen source in Thunder Bay. artemisia and grass are also present but at lower levels.
When is pollen season in Thunder Bay?
How often is the Thunder Bay pollen forecast updated?
The Thunder Bay pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in Thunder Bay 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 Thunder Bay 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 Thunder Bay, 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 pollen scores represent risk levels, not direct pollen measurements. Higher scores indicate higher risk.
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).
