The 8 cities where the hay fever season is now 29 days longer — full list

Millions of people with hay fever are suffering for longer each year as pollen becomes a “year-round problem” thanks to climate change, experts say. Research suggests the hay fever season now extends from spring to autumn in many parts of the UK, with the number of days when conditions are ripe rising significantly since 1994. Warmer weather during the months of May and June is thought to aid pollen production and cause plants to release their particles earlier and for longer.

The hay fever season grew by an average of 20 days in cities across England and Northern Ireland over the last three decades, and by 19 days in Scotland and Wales. The analysis was conducted by Round Our Way, a UK organisation which supports people impacted by weather extremes, and independent science group Climate Central.

Sofie Jenkinson, co-director of Round Our Way, said: “Hay fever is becoming an almost year-round problem for sufferers in the UK. As we all see around us, climate change is making Britain warmer and a lot wetter.

“We urgently need politicians to make sure we are better prepared for the worrying new weather we’re facing and to tackle the pollution that is causing it.”

Around 13 million people suffer from hay fever in the UK. The analysis looked at the length of the season in 236 cities.

The start was defined as when the maximum temperature recorded exceeded 13C for three consecutive days, and the end was when it dipped below that point for four consecutive days.

Overall, data showed an average of 187.1 days with conditions conducive to hay fever in England in 2024. This was up from 152.5 days in 1994.

Researchers then used statistical methods to account for annual fluctuations and estimated that the number of pollen-producing days had increased by 20.3 over that period.

Southern areas of England were worst affected, the research suggest. Eight cities that experienced the largest increase — of 29 days — were: Plymouth, Brentwood, Hornchurch, Grays, Romford, Basildon, Weymouth, and Colchester.

Pharmacist Vikki Furneaux, 44, from York, said the hay fever season was definitely becoming “longer, and also more erratic”.

She added: “When I graduated, people took medication for around a two-month period but now they are less sure when the season is, so it is more unpredictable when they need to take antihistamines.”

The earlier onset of symptoms also coincides with the end of the cold and flu season. Ms Furneaux added: “Some people are coming in with symptoms they didn’t realise were hay fever.”

The experts noted that some research also suggests that air pollution may make pollen grains more potent and more likely to trigger a reaction.

Michelle Young, climate impacts research associate at Climate Central, said: “Warmer spring and autumn temperatures, driven by climate change, are extending the pollen season, causing hay fever sufferers to experience symptoms earlier and for longer periods.

“As temperatures rise, allergy symptoms are becoming more frequent, sometimes occurring outside the typical peak times.

“Without significant reductions in emissions, this trend is expected to worsen, leading to greater discomfort for those with seasonal allergies.”