Harvest Hills, East Gwillimbury Pollen Forecast - Today, Tomorrow and the Week Ahead
Pollen Today
Today (11 October) pollen in Harvest Hills, East Gwillimbury is low; ragweed is low.
Pollen Tomorrow
Tomorrow (12 October 2026) ragweed increasing, grass at low levels, mugwort at low levels.
7-Day Trend
Over the next week grass, mugwort, and ragweed will decrease.
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Pollen Risk
Today - 11 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 | 3/100 |
Tomorrow - 12 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 | 17/100 | |
| Willow (Salicaceae) | None | 0/100 | — |
| Mugwort (Artemisia) | Low | 17/100 | |
| Ragweed (Ambrosia) | Moderate | 26/100 |
Local Environmental Conditions
The area around this location in East Gwillimbury is a mix of woodland and built-up land, plus a good deal of farmland. A stream or river nearby means riverside trees such as willow and poplar are part of the local pollen picture. Of the trees nearby, maple, ash and poplar are the ones that matter most for allergies. Grass pollen is significant here, and pigweed and plantain contribute weed pollen.
Tree pollen peaks in mid-spring, when the weather warms to around 5°C and maple, ash and poplar are in full flower. Grass pollen follows, peaking in early summer and easing off by early fall. The season closes with pigweed and plantain from early summer into early fall. By late fall, as temperatures fall to around 5°C, pollen levels are low again.
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Frequently Asked Questions About Pollen in Ontario
Is pollen high in East Gwillimbury right now?
On 11 October 2026, overall pollen levels in East Gwillimbury are low. Ambrosia is the main contributor to airborne pollen
Will pollen levels change in East Gwillimbury tomorrow?
On 12 October 2026, pollen conditions in East Gwillimbury will be different from today, with artemisia at low levels, grass at low levels and ambrosia increasing
Is pollen expected to decrease in East Gwillimbury 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 East Gwillimbury?
On 11 October 2026, Ambrosia is the dominant pollen source in East Gwillimbury. artemisia and grass are not currently active.
When is pollen season in East Gwillimbury?
How often is the East Gwillimbury pollen forecast updated?
The East Gwillimbury pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in East Gwillimbury 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 East Gwillimbury 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 East Gwillimbury, 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).
