Rayners Lane pollen forecast - today, tomorrow and the week ahead
Pollen Today
Today (20 September) pollen in Rayners Lane is moderate; mugwort is moderate.
Pollen Tomorrow
Tomorrow (21 September 2026) mugwort increasing.
7-Day Trend
Over the next week mugwort will increase; cypress, grass, and willow will remain stable.
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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) | None | 0/100 |
| Willow (Salicaceae) | None | 0/100 |
| Mugwort (Artemisia) | Moderate | 37/100 |
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 | 53/100 |
Local Environmental Conditions
Residents in Rayners Lane dealing with hay fever usually point to oak and birch as the culprits, particularly in spring near parks and gardens. The wider Harrow countryside supplies additional tree and grass pollen, particularly when the dominant maritime airflow carry it toward the built-up area. Overall exposure follows the broader regional trend, moderated somewhat by the town's parks and gardens.
In Rayners Lane, the pollen calendar starts with oak and rolls straight into birch. Oak pollen typically runs from April to May, while birch follows on from March to May. Grass then takes over from May right through September, peaking around June and July for most people. Good to know if you're planning anything outdoors that time of year.
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Frequently Asked Questions About Pollen in Harrow
Is pollen high in Rayners Lane right now?
On 20 September 2026, overall pollen levels in Rayners Lane are moderate. Artemisia is the main contributor to airborne pollen
Will pollen levels change in Rayners Lane tomorrow?
On 21 September 2026, pollen conditions in Rayners Lane will be different from today, with artemisia increasing
Is pollen expected to decrease in Rayners Lane this week?
According to the five-day outlook, artemisia pollen levels will increase later in the week.
Which pollen types are currently active in Rayners Lane?
On 20 September 2026, Artemisia is the dominant pollen source in Rayners Lane. willow, cypress, and grass are not currently active.
When is pollen season in Rayners Lane?
How often is the Rayners Lane pollen forecast updated?
The Rayners Lane pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in Rayners Lane 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 Rayners Lane 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 Rayners Lane, 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).
