Grass pollen is the UK's biggest hay fever trigger, affecting most sufferers. Here's when it peaks in 2026 and how to cope.
When is hay fever season in the UK?
UK hay fever season runs from late March to September, in three overlapping waves: tree pollen (late March–mid May), grass pollen (mid May–July, the peak for most sufferers) and weed pollen (June–September). 2026 follows the same pattern — grass pollen, the UK’s biggest trigger, peaks in June and early July.
2026 UK pollen calendar
| Month | Tree pollen | Grass pollen | Weed pollen |
|---|---|---|---|
| March | Medium–High | – | – |
| April | High | Low | – |
| May | Medium | High | Low |
| June | Low | Very High | Medium |
| July | – | High | Medium |
| August | – | Medium | High |
| September | – | Low | Medium |
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Grass pollen typically runs from late May through July, with the sharpest peak in June. Warm, dry, breezy days push counts highest; rain temporarily clears the air.
Reducing exposure
Keep windows shut during peak hours, run a bedroom air purifier overnight, dry washing indoors, and shower and change after being outside. Wraparound sunglasses and a balm around the nostrils help outdoors.
Treatment timing
Start antihistamines and nasal sprays before the peak. Track levels on the pollen map and see the wider grass pollen guide.
Practical next step: see our guide to the best air purifier for pollen allergy — model picks, room-size guidance and where to place a unit for the biggest overnight reduction.