Where the forecast comes from
pollen.ie uses the European air quality forecast from the Copernicus Atmosphere Monitoring Service (CAMS), through Open-Meteo. CAMS models how much pollen birch, alder, grass and weeds release each hour, based on the weather and the time of year, and where the wind carries it.
We combine that with a local weather forecast for each of the 32 counties and 63 larger towns, and update it every six hours.
What the levels mean
| Level | What to expect |
|---|---|
| Low | Few people notice symptoms. |
| Moderate | People with stronger hay fever may notice. |
| High | Most people with hay fever will notice. Plan around the worst hours. |
| Very high | Symptoms are likely. Keep time outside short and windows closed. |
A forecast, not a count
A pollen count is measured by a trap that samples the air, and is usually published a day or more later. A forecast tells you what to expect today and over the next few days, which is what you need to plan.
Real levels on your street can be higher or lower than the forecast, especially next to a field of long grass, under birch trees, or right after rain.
Why your town can differ from your county
Each town forecast is for the area around that town. Towns on the coast often have less pollen than inland ones, because sea breezes bring cleaner air. That is why a coastal town and the county around it can show different levels on the same day.
What we don’t forecast
CAMS covers birch, alder, grass, mugwort and ragweed. Hazel, ash, oak and nettle pollen and mould spores are not forecast directly, so treat the forecast as a guide for the main allergy seasons, not every possible trigger.
Questions
How accurate are pollen forecasts?
They are good at the timing of the season and at telling quiet days from bad ones. They can be off on the exact level for your street. Use the trend over a few days as well as today’s level.
Why does the forecast change during the day?
It updates every six hours with the latest weather. Rain, wind and temperature all change how much pollen is released and where it goes.
This is general information, not medical advice. If you are worried about symptoms, talk to your pharmacist or GP.