Watford pollen forecast - today, tomorrow and the week ahead
Pollen Today
Today (20 September) pollen in Watford is moderate; mugwort is moderate.
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) | Moderate | 30/100 |
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 | 46/100 |
Local Environmental Conditions
Locals with allergies tend to plan around two peaks a year rather than one long stretch. That's on top of sycamore and oak, which are the main local tree pollen sources around Watford's parks and quieter streets. Grass pollen from surrounding Hertfordshire fields is significant through the summer months, carried in by prevailing westerlies.
Pollen season in Watford really gets going with sycamore, followed not long after by oak. Sycamore pollen typically runs from April to June, with oak picking up between April and May. Grass pollen then stretches from May into September, with the worst of it typically landing in June and July. Useful to know if you tend to feel it every spring.
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Frequently Asked Questions About Pollen in Hertfordshire
Is pollen high in Watford right now?
On 20 September 2026, overall pollen levels in Watford are moderate. Artemisia is the main contributor to airborne pollen
Will pollen levels change in Watford tomorrow?
On 21 September 2026, pollen conditions in Watford will be similar to today, with artemisia at moderate levels
Is pollen expected to decrease in Watford this week?
According to the five-day outlook, artemisia pollen levels will increase later in the week.
Which pollen types are currently active in Watford?
On 20 September 2026, Artemisia is the dominant pollen source in Watford. willow, cypress, and grass are not currently active.
When is pollen season in Watford?
How often is the Watford pollen forecast updated?
The Watford pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in Watford 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 Watford 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 Watford, 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).
