Casa Loma, Toronto Pollen Forecast - Today, Tomorrow and the Week Ahead
Pollen Today
Today (10 October) pollen in Casa Loma, Toronto is low; ragweed, mold (alternaria), and mold (cladosporium) are low.
Pollen Tomorrow
Tomorrow (11 October 2026) ragweed remains low, mold (alternaria) remains low, mold (cladosporium) remains low, grass at low levels, mugwort at low levels.
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) | None | 0/100 |
| Willow (Salicaceae) | None | 0/100 |
| Mugwort (Artemisia) | None | 0/100 |
| Ragweed (Ambrosia) | Low | 6/100 |
| 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 | 14/100 | |
| Willow (Salicaceae) | None | 0/100 | — |
| Mugwort (Artemisia) | Low | 12/100 | |
| Ragweed (Ambrosia) | Low | 24/100 | |
| Mold (Alternaria) | Low | 4/100 | |
| Mold (Cladosporium) | Low | 12/100 |
Local Environmental Conditions
This site in Toronto sits among a blend of built-up land and woodland. Of the allergenic trees nearby, maple matters most, while oak also contributes. Grasses and weeds such as ragweed and plantain round out the local mix. Ragweed is unusually common here compared with most other locations, making it a particularly important local pollen source.
Tree pollen peaks in mid-spring, when the weather warms to around 5°C and maple and oak are in full flower. Grasses take over in early summer, with temperatures around 20°C, and their pollen lingers into early fall. Ragweed and plantain bring the strongest peak of the year from late summer into mid-fall. By late fall, pollen levels are low again.
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Frequently Asked Questions About Pollen in Ontario
Is pollen high in Toronto right now?
On 10 October 2026, overall pollen levels in Toronto are low. Ambrosia is the main contributor to airborne pollen
Will pollen levels change in Toronto tomorrow?
On 11 October 2026, pollen conditions in Toronto will be different from today, with ambrosia at low levels, artemisia at low levels, grass at low levels
Is pollen expected to decrease in Toronto 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 Toronto?
On 10 October 2026, Ambrosia is the dominant pollen source in Toronto. artemisia and grass are not currently active.
When is pollen season in Toronto?
How often is the Toronto pollen forecast updated?
The Toronto pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in Toronto 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 Toronto 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 Toronto, 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).
