Ottawa Pollen Forecast - Today, Tomorrow and the Week Ahead
Pollen Today
Today (10 October) pollen in Ottawa is moderate; mold (cladosporium) is moderate; grass, mugwort, ragweed, and mold (alternaria) are low.
Pollen Tomorrow
Tomorrow (11 October 2026) grass remains low, ragweed remains low, mold (alternaria) remains low, mold (cladosporium) remains moderate, mugwort no longer expected.
7-Day Trend
Over the next week grass and mugwort will increase; 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 | 9/100 |
| Willow (Salicaceae) | None | 0/100 |
| Mugwort (Artemisia) | Low | 7/100 |
| Ragweed (Ambrosia) | Low | 11/100 |
| Mold (Alternaria) | Low | 21/100 |
| Mold (Cladosporium) | Moderate | 38/100 |
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 | 4/100 | |
| Willow (Salicaceae) | None | 0/100 | — |
| Mugwort (Artemisia) | None | 0/100 | |
| Ragweed (Ambrosia) | Low | 12/100 | |
| Mold (Alternaria) | Low | 16/100 | |
| Mold (Cladosporium) | Moderate | 28/100 |
Local Environmental Conditions
Built-up land makes up around 46% of the area near the heart of Ottawa, with some woodland and open water. Close to a stream or river, riverside vegetation contributes to what is in the air. Woodland on all sides makes trees an important local pollen source. Grass pollen is a substantial part of the local mix as well.
Tree pollen comes first, peaking in mid-spring. Then come the grasses, strongest in late spring and fading by early fall. A smaller weed peak follows from early summer into early fall. Summer is the wettest time of year, and heavy showers can bring short breaks in pollen. 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 Illinois
Is pollen high in Ottawa right now?
On 10 October 2026, overall pollen levels in Ottawa are low. Grass is the main contributor to airborne pollen, while ambrosia and artemisia remain at lower levels
Will pollen levels change in Ottawa tomorrow?
On 11 October 2026, pollen conditions in Ottawa will be different from today, with grass at low levels, ambrosia at low levels
Is pollen expected to decrease in Ottawa this week?
According to the five-day outlook, ambrosia pollen levels are expected to gradually decrease, while grass and artemisia pollen will increase, suggesting mixed conditions later in the week.
Which pollen types are currently active in Ottawa?
On 10 October 2026, Grass is the dominant pollen source in Ottawa. ambrosia and artemisia are also present but at lower levels.
When is pollen season in Ottawa?
How often is the Ottawa pollen forecast updated?
The Ottawa pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in Ottawa 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 Ottawa 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 Ottawa, 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).
