It’s not in your head.
Climate change is making pollen seasons longer and more severe across the Northern Hemisphere. Dr. Neelima Tummala, an otorhinolaryngologist at New York University Langone Health, said patients tell her every year that their allergies are the worst ever, and that may be true.
Approximately one-quarter of adults and one in five children in the United States have seasonal allergies. For millions of Americans, spring weather brings sniffles, itchy eyes, asthma flare-ups, and other distressing symptoms that range from mild symptoms to serious medical emergencies.
Pollen season is currently worsening across the country due to rising temperatures and carbon pollution. Heat waves, air pollution, and natural disasters caused by climate change can also worsen allergy symptoms.
Experts say it’s too early to tell for sure how the 2026 pollen season will compare to past years, but the trends of recent decades are clear and the evidence so far suggests it’s going to be another tough year for allergy-prone people.
Spring blooms have arrived early in most parts of the country, according to the American Seasonal Network, an organization focused on data and research on seasonal patterns in plants and animals.
AccuWeather meteorologists say this year’s trends fit into an overall pattern of longer allergy seasons due to climate change.
They predict high levels of tree pollen in the Ohio River Valley and parts of the Pacific Northwest this spring, and say the Northern Plains and Great Lakes could see an early spike in grass pollen in June and July due to a combination of wetter and warmer weather. A heavy weed pollen season is expected in the Rocky Mountains, while in parts of New England and the southern Gulf Coast, a colder spring and less rain could result in lower-than-normal tree pollen levels, researchers said.
Climate change and pollen
As global warming shortens winters and melts snow earlier, trees begin blooming and producing pollen earlier in spring.
A 2021 study found that human-induced climate change is worsening North America’s pollen season. And Climate Central found that in most of the 198 U.S. cities the group analyzed, the “freeze-free growing season” increased by an average of 21 days from 1970 to 2025. The average increase was highest in the northwest and southwest.
“The symptoms are the same, just more severe.”
— Moshe Ben Shoshan, Montreal Children’s Hospital
High concentrations of carbon dioxide directly increase pollen production, which could increase by up to 200 percent by the end of the century, according to a 2022 study published in Nature Communications.
Moshe Ben-Shoshan, a pediatric allergist at Montreal Children’s Hospital, said pollen counts are increasing worldwide, but are particularly well-studied in North America and northern Europe.
Some Ben Shoshan patients are experiencing more severe symptoms, and treatments that once worked, such as antihistamines and nasal sprays, no longer control their symptoms.
“It’s the same symptoms, just more intense,” he said.
As climate change delays the first frost of winter in much of North America, summer ragweed will bloom for longer, extending the second half of the pollen season into fall, said David Weese, a lecturer in horticulture at McGill University in Montreal.
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Weese herself suffers from seasonal allergies and has noticed that her symptoms start earlier and last longer.
“There are some birch trees outside my office,” he said. “I know because my nose gets stuffy and my eyes get itchy.”
Pollen is not the only allergen affected by climate change. Increased humidity, heat, and flooding create ideal conditions for mold to grow in areas where it rarely existed before.
As a result, mold allergies can come back, especially in the aftermath of climate change disasters such as hurricanes, or in patients who live in older buildings, basements or other homes without proper ventilation, Tummala said.
pollen accumulates
For many people, seasonal allergies are primarily a nuisance. Itchy eyes, runny nose, and a never-ending cold. But pollen can pose more serious risks by disrupting sleep, increasing the risk of sinus infections, and causing people to miss school or work.. A 2024 Texas-based study found that pollen may account for a significant portion of emergency room visits for asthma attacks during periods of high pollen counts.
Dr. Neelima Tummala is an otolaryngologist at NYU Langone Health. Credit: New York University
People with allergies are also more sensitive to other respiratory disease triggers, such as heat waves and increased air pollution, Tummala said.
On days with heavy wildfire smoke from Canada, patients experience the devastating effects of multiple respiratory stressors, Tummala said. During one such time last summer, one patient told her that he was afraid to go outside.
“It’s really sad,” Tummala said. “That’s not how you should live your life.”
Drought is also a problem that is exacerbated by climate. Rain usually washes pollen out of the air. Without this, Weese said, fine powder could be floating around unmitigated for weeks.
Tummala said the link between seasonal allergies and increasing climate change further demonstrates the already pressing need for measures to mitigate global warming.
“This is a modifiable risk factor,” she says. “Climate change is something we can do something about.”
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Keerthi Gopal
health and justice reporter
Keerti Gopal covers the intersection between climate change, public health, and environmental justice for Inside Climate News. Previously, we covered climate change activism and the suppression of movements. She is a National Geographic Explorer and has received fellowships from Fulbright, Solutions Journalism Network, The Lever, and the National Press Foundation.
