Allergy season is no fun when dealing with sniffling, sneezing, coughing, and watery eyes. Unfortunately, this dreaded period is getting longer throughout the United States because of climate change, according to Climate Central’s report, Seasonal Allergies: Pollen and Mold, which reviews weather and climate trends impacting pollen seasons and related health risks. This is bad news for about one in four adults and one in five children who suffer each year from seasonal allergy symptoms.
The report analyzed trends from 2022 through 2024 and projected what will happen this year. It showed significant shifts in both the timing and intensity of allergy seasons across several regions, particularly a consistent pattern of prolonged allergy seasons. Spring allergies are starting earlier, while autumn allergies are lasting later into the year. On average, the allergy season is about two weeks longer than it used to be.
Here we’ll discuss why this is happening now, what regions are most impacted, predictions for the coming months, and how you can prepare your home for an intense allergy season.
Reasons for a Prolonged Allergy Season
The longer allergy season is the result of a warming climate. The research by Climate Central indicates that the freeze-free growing season—the number of consecutive days with minimum temperatures above 32 degrees Fahrenheit—has expanded by 20 days, on average. Temperatures above freezing allow for better plant growth. This means that plants now have more time to produce pollen, which triggers more allergies.
Warmer temperatures also aid in plants’ productivity. The amount of pollen produced by each plant is about 20 percent higher than in previous allergy seasons. The pollen is more potent as well, which can lead to more intense allergy symptoms.
What’s also interesting is that higher levels of carbon dioxide in the air boost pollen production in plants, especially ragweed and grasses.
Where the Shifts Are Taking Place
Certain areas of the country are experiencing the most dramatic changes in seasonal allergy patterns. In South cities, such as Houston and Atlanta, warmer winters have led to earlier tree pollen production, while longer summers are pushing allergies further into the fall. Along the West Coast, cities are seeing higher pollen counts during what are typically mild times of the year. Even in the Mountain states, which have been known for short allergy seasons, they are now recording increases in the length of allergy seasons as well.
Specific examples help paint the picture. The growing season, which affects allergy season, is now more than 50 days longer than it was in the 1970s in places like Medford, Oregon, and Myrtle Beach, South Carolina. And in Reno, Nevada, the season is now more than three months longer than in the past.
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Predictions for the 2025 Allergy Season
One of the most important aspects of the report is the predictions for 2025 so more people can plan for allergy season. Expect extended allergy seasons this spring, specifically up to 3 weeks earlier than what typically occurs. Fall allergies are predicted to last longer into winter, especially in southern states. This could result in these two separate allergy seasons actually overlapping.
Experts also predict allergens to appear in more areas, including places where they used to be uncommon. Northern states, for example, may experience allergens that are frequently found in southern regions. Another possibility: the intensity of allergens could also shift, with short but intense allergy seasons becoming more common.
How to Prepare Your Home for Allergy Season
Nobody wants to be miserable in their own home. Fortunately, there are several strategies to minimize the impact of allergy season while you are relaxing indoors.
- Keep all windows sealed and closed so pollen stays out of your house. If it’s warm and/or stuffy, run the air conditioner to improve airflow during allergy season.
- Take a shower before bedtime to wash pollen off your body and prevent pollen from transferring to your sheets and pillow.
- Invest in high-efficiency particulate air (HEPA) filters for vacuums and air purifiers.
- Regularly clean your home, including vacuuming carpets, dusting surfaces, and mopping floors, to reduce the presence of allergens.
- Control humidity levels with dehumidifiers and air conditioners to maintain a dry environment.
- Avoid hanging laundry outside so your clothing doesn’t pick up pollen and bring it into your home.
- Remove shoes at the door before entering your home.
- Purify the air by displaying certain plants throughout your home and avoiding those that are worst for allergies.
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