Guelph pollen forecast — Westminster Woods Neighbourhood Group neighborhood
Pollen Today
Today (20 September) pollen in Westminster Woods Neighbourhood Group, Guelph 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 | 33/100 |
| Willow (Salicaceae) | None | 0/100 |
| Mugwort (Artemisia) | Low | 9/100 |
| Ragweed (Ambrosia) | Moderate | 43/100 |
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 | 3/100 | |
| Willow (Salicaceae) | None | 0/100 | — |
| Mugwort (Artemisia) | None | 0/100 | |
| Ragweed (Ambrosia) | Low | 14/100 |
Local Environmental Conditions
Located close to this spot, this area has hazel and willow grow along the bank, contributing some of the season's earliest allergenic pollen. This area, close to home here, has a wooded area built around oak and birch, both contributing heavily to the region's spring pollen totals. Maintained parkland where turf grass and ornamental species add to the grass and ragweed mix, just outside the immediate area.
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. Woodland oak and birch pick up the pace next, through mid-to-late spring, typically landing in April and May. Grass pollen builds through late spring and peaks in June, and ragweed later takes the lead from mid-August through October.
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Frequently Asked Questions About Pollen in Ontario
Is pollen high in Guelph right now?
On 20 September 2026, overall pollen levels in Guelph are moderate. Grass is the main contributor to airborne pollen, while ambrosia and artemisia remain at lower levels
Will pollen levels change in Guelph tomorrow?
On 21 September 2026, pollen conditions in Guelph will be different from today, with grass, ambrosia continuing to decline
Is pollen expected to decrease in Guelph this week?
According to the five-day outlook, grass, ambrosia, and artemisia pollen levels will increase later in the week.
Which pollen types are currently active in Guelph?
On 20 September 2026, Grass is the dominant pollen source in Guelph. ambrosia and artemisia are also present but at lower levels.
When is pollen season in Guelph?
How often is the Guelph pollen forecast updated?
The Guelph pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in Guelph 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 Guelph 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 Guelph, 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).
