Halton Hills pollen forecast — Marywood Meadows neighborhood
Pollen Today
Today (20 September) pollen in Marywood Meadows, Halton Hills is high; ragweed is high; grass is 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 | 40/100 |
| Willow (Salicaceae) | None | 0/100 |
| Mugwort (Artemisia) | Low | 9/100 |
| Ragweed (Ambrosia) | High | 54/100 |
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 | 8/100 | |
| Willow (Salicaceae) | None | 0/100 | — |
| Mugwort (Artemisia) | None | 0/100 | |
| Ragweed (Ambrosia) | Low | 22/100 |
Local Environmental Conditions
Located within easy reach, this area has the nearest stream or river hosts hazel and willow, two of the most allergenic early-season trees. Nearby, just outside the immediate area, woods composed largely of oak and birch, a combination tied to sharp spring pollen spikes. Grass and ornamental trees within the park boundary contribute modestly to grass and ragweed levels, within the neighborhood.
Water-edge hazel and willow are usually the first allergenic trees active here, usually the first pollen source active, peaking sometime in February or March. Oak and birch in the nearby woodland follow in mid-to-late spring, typically the year's sharpest tree-pollen spell, centered on April and May. By late spring, grass pollen is climbing steadily toward a June high point, before ragweed becomes the more dominant allergen from mid-August into October.
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Pollen forecast neighborhoods 6 neighborhoods
Sports venues in Halton Hills 1 sports venue
Frequently Asked Questions About Pollen in Ontario
Is pollen high in Halton Hills right now?
On 20 September 2026, overall pollen levels in Halton Hills are high. Ambrosia is the main contributor to airborne pollen, while grass and artemisia remain at lower levels
Will pollen levels change in Halton Hills tomorrow?
On 21 September 2026, pollen conditions in Halton Hills will be different from today, with ambrosia, grass continuing to decline
Is pollen expected to decrease in Halton Hills 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 Halton Hills?
On 20 September 2026, Ambrosia is the dominant pollen source in Halton Hills. grass and artemisia are also present but at lower levels.
When is pollen season in Halton Hills?
How often is the Halton Hills pollen forecast updated?
The Halton Hills pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in Halton Hills 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 Halton Hills 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 Halton Hills, 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).
