Allergy Season Lengthens Across U.S. Due to Climate Change

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According to newly released data from Climate Central, allergy season has grown longer in every part of the United States since the 1970s, with an average increase of 21 extra 'freeze-free' days. This gives plants more time to grow and release the pollen that causes seasonal allergies for many people.

Why it matters

The lengthening of allergy season is a direct result of climate change, as warmer temperatures and fewer freezing days allow plants to bloom and release pollen for a longer period each year. This is causing increased suffering for those with seasonal allergies and highlighting the real-world impacts of a changing climate.

The details

The Climate Central analysis looked at temperature data across the country and found that the number of 'freeze-free' days - days without freezing temperatures - has increased significantly over the past several decades. This extended growing season gives plants more time to grow, flower, and release pollen, exacerbating allergy symptoms for many Americans.

• The analysis looked at data from the 1970s to the present day.
• Allergy season has grown by an average of 21 extra 'freeze-free' days across the United States since the 1970s.

What’s next

Climate Central plans to continue monitoring temperature and allergy season data to further understand the impacts of climate change on public health.