Why Climate Change Is Making Allergies Worse—and What to Expect Next

Climate Change Is Extending and Intensifying Allergy Seasons

Climate change is worsening seasonal allergies by creating longer and more intense pollen seasons, according to extensive research from scientists and physicians. Rising global temperatures are altering pollen production, timing, and distribution, leading to more persistent and severe allergy symptoms.

“We know that climate change is leading to greater amounts of pollen in the atmosphere. It’s changing the seasonality of the pollen. It’s changing the types of pollen that we’re exposed to.”

— Paul Beggs, environmental health scientist and professor at Macquarie University in Sydney, Australia (2024 study on climate change and asthma)

2026 Allergy Forecast Predicts More High-Pollen Days

With pollen season already underway in many parts of the U.S., the AccuWeather 2026 US Allergy Forecast anticipates an increase in high-pollen days this year. Factors such as storms and temperature fluctuations are driving this trend.

“The data is clear, and millions of seasonal allergy sufferers have noticed the changes. The seasonal allergy season in America is expanding at both ends.”

— Brett Anderson, AccuWeather climate expert and senior meteorologist

Allergy Seasons Are Starting Earlier and Lasting Longer

Dr. Rebecca Saff, an allergist and immunologist at Massachusetts General Hospital in Boston, notes that allergy seasons are no longer confined to spring or fall. Warmer winters and earlier springs are pushing allergy seasons to begin sooner and extend further into the year.

A 2022 study published in Nature projects that by the end of the century, pollen seasons will start 40 days earlier and end 15 days later than current patterns.

“Later frost dates mean the allergy season is ending later in many places. When warmth and moisture align, trees, grass, and weeds can produce more pollen more often.”

— Brett Anderson

New Allergens Are Emerging as Plants Shift Northward

Rising temperatures are enabling plants like ragweed to migrate northward, introducing new allergens to regions where they were previously uncommon. This shift is particularly noticeable in the Northeast, where ragweed and other allergenic plants are becoming more prevalent.

According to the World Meteorological Organization (WMO), the past 11 years have been the 11 warmest on record. These extreme temperatures are contributing to what experts describe as alarming allergy events, as reported by the BBC.

30% of Americans Now Affected by Seasonal Allergies

Today, 30% of Americans over the age of 18 suffer from seasonal allergies, according to the Centers for Disease Control and Prevention (CDC). Climate change is prolonging symptoms such as watery eyes, sneezing, and coughing, making allergies a growing public health concern.

Key Takeaways:

• Climate change is extending pollen seasons, leading to longer allergy periods.
• Rising temperatures are causing plants like ragweed to spread into new regions.
• The 2026 Allergy Forecast predicts more high-pollen days in the U.S.
• By 2100, pollen seasons may start 40 days earlier and end 15 days later.
• 30% of U.S. adults now experience seasonal allergies, with symptoms lasting longer.