Llantrisant pollen forecast - today, tomorrow and the week ahead
Pollen Today
Today (20 September) pollen in Llantrisant is low; mugwort is low.
Pollen Tomorrow
Tomorrow (21 September 2026) mugwort increasing, grass at low levels.
7-Day Trend
Over the next week grass and mugwort will decrease; cypress and willow will remain stable.
Explore Forecasts
Air Quality
Pollen in Other Cities
Air Quality in Other Cities
Get More in Our App
Local pollen and air quality forecasts, interactive pollen maps and route profiles
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 | 22/100 |
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) | Low | 5/100 | |
| Willow (Salicaceae) | None | 0/100 | |
| Mugwort (Artemisia) | Moderate | 42/100 |
Local Environmental Conditions
Around Llantrisant, ash and hazel are the dominant species behind local tree pollen, with counts higher near parks than in the centre. The wider Rhondda Cynon Taf countryside supplies additional tree and grass pollen, particularly when prevailing westerlies carry it toward the built-up area. This mix of urban and rural influence gives Llantrisant a fairly typical pollen pattern for the wider region.
So here's the rundown for Llantrisant: ash pollen shows up first, then hazel takes over. Grass pollen then stretches from May into September, with the worst of it typically landing in June and July. Ash tends to release pollen between March and May, while hazel follows on from January to April. Useful to know if you tend to feel it every spring.
Get pollen & AQ on Strava
Follow your environmental exposure and performance with the free Airmine-Strava integration. See your pollen and air quality exposure for every Strava activity.
Resource Hub
Frequently Asked Questions About Pollen in Rhondda Cynon Taf
Is pollen high in Llantrisant right now?
On 20 September 2026, overall pollen levels in Llantrisant are low. Artemisia is the main contributor to airborne pollen
Will pollen levels change in Llantrisant tomorrow?
On 21 September 2026, pollen conditions in Llantrisant will be different from today, with grass at low levels and artemisia increasing
Is pollen expected to decrease in Llantrisant this week?
According to the five-day outlook, grass and artemisia pollen levels are expected to gradually decrease, suggesting improving conditions later in the week.
Which pollen types are currently active in Llantrisant?
On 20 September 2026, Artemisia is the dominant pollen source in Llantrisant. grass, willow, and cypress are not currently active.
When is pollen season in Llantrisant?
How often is the Llantrisant pollen forecast updated?
The Llantrisant pollen forecast is updated four times daily. See the timestamp below for the most recent update.
Does pollen in Llantrisant 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 Llantrisant 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 Llantrisant, 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).
