The Met Office publishes a pollen forecast through the season, and the useful part is not the overall level but which pollen type is driving it.
Broadly, in the UK:
- Tree pollen: late March to mid-May — birch is the big one for allergy
- Grass pollen: mid-May to July, and the most common trigger by a distance
- Weed pollen: late June into September
If you are allergic to grass and the count is high because of tree pollen, that day may be fine for you. Knowing your trigger converts a general forecast into a personal one.
Finding Out Which Pollen Affects You
Track when your symptoms actually start and stop across a season and compare with the calendar above. If your bad weeks are consistently late May to July, grass is the likely culprit. Allergy testing through a GP or allergy service can confirm it where it matters — for instance, before considering immunotherapy, which is allergen-specific.
What the Weather Is Telling You
- Warm, dry, breezy — pollen released and carried, high counts
- Rain — washes pollen out of the air, usually a good day
- Humid and still after warm weather — pollen hangs around at lower level
- Thunderstorms during grass season — a recognised risk period, particularly for people with asthma
Counts are typically highest in the early morning as pollen is released, and again in the early evening as air cools and pollen descends.
Be Wary of "Worst Season Ever"
Every spring produces claims of a record pollen year, usually attached to something being sold. Asked directly in 2026, the Met Office said it had no data supporting the claim that pollen was worse that year — what had happened was that grass and weed seasons started earlier and stronger after warm late-May weather, and dry conditions kept pollen airborne.
The longer-term picture is more measured too. UKHSA's assessment is that warmer temperatures can bring earlier and longer seasons and that the spread of allergenic plants such as ragweed is worth watching — which is a real trend, and not the same as any given year being a record.
What Actually Reduces Exposure
In rough order of usefulness:
- Shower and change clothes when you come in on a high-pollen day. Pollen travels home in your hair and on your clothing.
- Dry washing indoors during your season. Sheets hung outside collect pollen that you then sleep in.
- Keep bedroom windows shut early morning and evening, when counts peak.
- Wraparound sunglasses, which genuinely help eye symptoms.
- A barrier balm around the nostrils before going out, to trap pollen.
- Car air recirculation, with a pollen filter if your car has one.
Using the Forecast to Time Treatment
The forecast is most valuable at the start of your season, not during it. Antihistamines and especially steroid nasal sprays work best when started before symptoms establish — two to four weeks ahead, with the spray needing one to two weeks of daily use to reach full effect.
Watching the forecast to decide whether to take a tablet today is using it backwards. Watching it to know when your season is beginning is using it well.