Extreme weather and warming temperatures fueled by climate change make pollen seasons longer, more intense, worsening seasonal pollen allergies for millions

Washington D.C., March 10, 2026 — The Asthma and Allergy Foundation of America (AAFA) today released its annual Allergy Capitals® report ranking the most challenging cities in the U.S. to live with seasonal pollen allergies. More than 106 million people in the U.S. experience various types of allergies each year, including many with pollen allergies.

This year, Boise, Idaho, claimed the top spot due to higher-than-average pollen levels and relatively low availability of allergy specialists. Boise moved into the top spot due to tree pollen peaking earlier and lasting longer as well as a significant increase in the number of days with “high” or “very high” grass pollen.  The effects of climate change helped drive Boise’s climb to the top of the rankings.

“Allergies disrupt sleep, undermine concentration, keep children home from school, and keep adults from work. We are experiencing a widening health threat fueled by climate change,” said Kenneth Mendez, President and CEO of AAFA. “Millions of people in the U.S. live with seasonal pollen allergies, and extreme weather events driven by climate change contribute to the conditions that lead to higher pollen levels and longer allergy seasons. This report is a call to action for policymakers: We need climate solutions, and we need them now.”

The report’s data paints a devastating picture of the current climate reality. Extreme weather events – including atmospheric rivers, warmer temperatures, and drought – are becoming more common. These events help create the conditions for longer, more intense pollen seasons, meaning many people in the U.S. experience nearly year-round exposure to some type of pollen.

AAFA’s Allergy Capitals ranking scores the top 100 most populated city areas in the contiguous United States based on annual pollen counts, over-the-counter allergy medicine use, and number of allergists. The full report can be found at allergycapitals.org

The top 20 Allergy Capitals® for 2026 (out of 100 cities ranked) are:

The impact of longer, more intense pollen seasons goes beyond simply more sneezing. Pollen is a common trigger of allergic asthma, allergic rhinitis, allergic conjunctivitis, atopic dermatitis, nasal polyps, and eosinophilic esophagitis.

“Long and potent pollen seasons make managing allergies and asthma more challenging, leading to increased health care costs and missed days of school and work,” said AAFA Chief Mission Officer Melanie Carver. “At the individual level, allergy management strategies will help reduce symptoms. But long-term and wide-scale solutions require policymakers at all levels of government to adopt strategies to address the climate and health crisis.”

AAFA’s Allergy Capitals report includes both strategies for allergy management and recommendations for policymakers.

“Monitoring pollen counts is a key strategy in managing pollen allergy,” said Kris Klein, CEO of Pollen Sense. “When you are aware of pollen levels, you can make an informed decision about time spent outdoors. Pollen Sense is proud to work with AAFA in support of this annual report. As extreme weather events bring high pollen counts to more parts of the country, it is critical that communities understand the impact of pollen. This report provides both tools for understanding pollen allergies and actionable insight to promote policy change.”

The 2026 Allergy Capitals report is an independent research project of the Asthma and Allergy Foundation of America and made possible by support from Opella, makers of Allegra®.

Resources:

• 2026 Allergy Capitals® report: allergycapitals.org
• Allergy facts and stats: aafa.org/allergyfacts
• Pollen allergy: aafa.org/pollen
• Allergy medicine guide: aafa.org/allergymeds