Santo Tirso pollen forecast - today, tomorrow and the week ahead
Pollen Today
Today (20 September) pollen in Santo Tirso is high; mugwort is high.
Pollen Tomorrow
Tomorrow (21 September 2026) levels are similar to today.
7-Day Trend
Over the next week mugwort will increase; cypress, grass, and willow will remain stable.
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Features and forecast availability vary by region.
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) | None | 0/100 |
| Willow (Salicaceae) | None | 0/100 |
| Mugwort (Artemisia) | High | 70/100 |
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) | None | 0/100 | |
| Willow (Salicaceae) | None | 0/100 | |
| Mugwort (Artemisia) | High | 70/100 |
Local Environmental Conditions
Santo Tirso's parks and the Ave River corridor oak and eucalyptus make up the bulk of the tree pollen locally, and grass from local Porto land adds to it through spring. Onshore breezes off the Atlantic help disperse counts quickly.
The pollen year in Santo Tirso starts with oak and eucalyptus, builds through a grass-driven spring, and is regularly interrupted by Atlantic rain and onshore wind, spanning January through June. Southerly stretches of coastline tend to see an earlier, warmer start to the season.
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Frequently Asked Questions About Pollen in Porto
Is pollen high in Santo Tirso right now?
On 20 September 2026, overall pollen levels in Santo Tirso are high. Artemisia is the main contributor to airborne pollen
Will pollen levels change in Santo Tirso tomorrow?
On 21 September 2026, pollen conditions in Santo Tirso will be similar to today, with artemisia at high levels
Is pollen expected to decrease in Santo Tirso this week?
According to the five-day outlook, artemisia pollen levels will increase later in the week.
Which pollen types are currently active in Santo Tirso?
On 20 September 2026, Artemisia is the dominant pollen source in Santo Tirso. cypress, grass, and willow are not currently active.
When is pollen season in Santo Tirso?
How often is the Santo Tirso pollen forecast updated?
The Santo Tirso pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in Santo Tirso 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 Santo Tirso 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 Santo Tirso, 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).
