Climate change is making your allergies worse, in part by creating longer and more intense pollen seasons, according to a growing body of research from a number of scientists and physicians.
“We know that climate change is leading to greater amounts of pollen in the atmosphere,” says Paul Beggs, an environmental health scientist and professor at Macquarie University in Sydney, Australia, who published a 2024 paper on the link between climate change and asthma. “It’s changing the seasonality of the pollen. It’s changing the types of pollen that we’re exposed to.”
With pollen season already underway in many parts of the U.S., the AccuWeather 2026 U.S. Allergy Forecast is predicting more high-pollen days this year, driven by variables like storms and temperature swings.
“The data is clear, and millions of seasonal allergy sufferers have noticed the changes,” AccuWeather climate expert and senior meteorologist Brett Anderson says. “The seasonal allergy season in America is expanding at both ends.”
Dr. Rebecca Saff, an allergist and immunologist at Massachusetts General Hospital in Boston, agrees that long gone are the days when allergies were restricted to merely spring or fall. As global warming creates shorter, milder winters and warmer springs, those allergy seasons start earlier and continue later.
And a 2022 study in the journal Nature predicts pollen season will start 40 days earlier and end 15 days later by the end of the century.
“Later frost dates mean the allergy season is ending later in many places,” Anderson says. “When warmth and moisture align, trees, grass, and weeds can produce more pollen more often.”
According to Saff, those warmer temps are contributing to some plants migrating north, like ragweed—giving way to new allergens that weren’t previously seen in some parts of the country, such as the Northeast.
At the same time, rising temperatures—the World Meteorological Organization (WMO) says the past 11 years have been the 11 warmest on record—are triggering what experts call alarming extreme allergy events, the BBC reported.
Today, 30% of Americans over the age of 18 have seasonal allergies, according to the Centers for Disease Control and Prevention (CDC). Now, thanks to climate change, they could see symptoms like watery eyes, sneezing, and coughing lasting longer.