Climate change has extended Europe's pollen season by up to two weeks, prolonging hay fever symptoms compared with the 1990s, according to a review published in the journal Lancet Public Health. The report, authored by 65 scientists, examined birch, alder, and olive trees in Europe and found that pollination started one to two weeks earlier during 2015 to 2024 compared with 1991 to 2000.

"We are seeing a prolonged season – an earlier onset of pollination in both the north and south [of Europe]." said Professor Joacim Rocklov of the University of Heidelberg. Rocklov said more research is needed to determine whether climate change increases pollen amounts and makes hay fever symptoms more severe.

Early summer is often peak pollen season, when the number of pollen grains in the air increases, and warm, dry days help spread pollen through the air. Warm weather in the UK over the last two years created conditions for birch tree pollen release. Pollen from grasses, trees, and plants can trigger itchy eyes, sneezing, and headaches in people with pollen allergies.

"While for some their symptoms can be mild, for many their hay fever symptoms impacts their quality of life." said Anne Biggs, Deputy Head of Clinical Services at Allergy UK. "It can mean missed days at work, poor sleep and, for some teenagers and young people, active hay fever symptoms can mean they drop an academic grade in their exams." she said.

Dr Samantha Walker, Director of Research and Innovation at Asthma and Lung UK, pointed to more severe health consequences for some sufferers. "If people are allergic to pollen, it can inflame their airways and cause terrifying breathing conditions, which can lead to life-threatening asthma attacks and COPD flare-ups." Walker said.

There is no cure for hay fever, but medicines can relieve symptoms, and products can be bought over the counter at local pharmacies. The NHS recommends using nasal balm or petroleum jelly around nostrils to trap pollen, wearing sunglasses, a mask or a wide-brimmed sun hat, vacuuming and dusting the home regularly, and trying a pollen filter in car air vents. The NHS also advises avoiding mowing or walking on grass, keeping fresh flowers in the house, smoking or exposure to tobacco smoke, and drying clothes outdoors. Pets can carry pollen into the home.

A general practitioner can refer patients with severe hay fever to a specialist, though referrals may take time. Immunotherapy treatment might be available for people with severe hay fever, which involves injecting tiny amounts of pollen into the body over time to build tolerance and reduce allergic reactions.