Alphen aan den Rijn pollen forecast - today, tomorrow and the week ahead
Pollen Today
Today (20 September) pollen in Alphen aan den Rijn is low; mugwort is low.
Pollen Tomorrow
Tomorrow (21 September 2026) mugwort increasing.
7-Day Trend
Over the next week grass and mugwort will increase; cypress 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) | Low | 15/100 |
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) | Moderate | 33/100 |
Local Environmental Conditions
Alphen aan den Rijn's Oude Rijn River corridor and surrounding green spaces feature oak, birch, and alder as the main tree pollen sources, with exposure varying between the riverside areas and the more built-up city centre. Surrounding South Holland farmland and the flat, open polder landscape contribute substantial grass and crop pollen, while the river valley channels airflows and concentrates pollen.
Alphen aan den Rijn's pollen season runs from January through August, opening with hazel and alder from January before birch peaks through April. Oak and ash follow through April and May, with grass peaking through June and July. The Oude Rijn valley channels airflows, while surrounding South Holland farmland and the flat polder landscape extend substantial grass and crop pollen into August.
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Resource Hub
Local parkruns 1 parkrun
Frequently Asked Questions About Pollen in Zuid-Holland
Is pollen high in Alphen aan den Rijn right now?
On 20 September 2026, overall pollen levels in Alphen aan den Rijn are low. Artemisia is the main contributor to airborne pollen
Will pollen levels change in Alphen aan den Rijn tomorrow?
On 21 September 2026, pollen conditions in Alphen aan den Rijn will be different from today, with artemisia increasing
Is pollen expected to decrease in Alphen aan den Rijn this week?
According to the five-day outlook, grass and artemisia pollen levels will increase later in the week.
Which pollen types are currently active in Alphen aan den Rijn?
On 20 September 2026, Artemisia is the dominant pollen source in Alphen aan den Rijn. cypress, grass, and willow are not currently active.
When is pollen season in Alphen aan den Rijn?
How often is the Alphen aan den Rijn pollen forecast updated?
The Alphen aan den Rijn pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in Alphen aan den Rijn 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 Alphen aan den Rijn 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 Alphen aan den Rijn, 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).
