Allergy Season Lengthens Across the US

Climate change extends the time plants have to grow and release pollen

Published on Mar. 5, 2026

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New data from Climate Central shows that since the 1970s, allergy season has grown longer in every part of the United States, by an average 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

As the climate continues to change, the extended allergy season poses health challenges for those who suffer from seasonal allergies. Longer allergy seasons can lead to increased medication use, doctor visits, and missed work or school days.

The details

The data from Climate Central shows that the length of the allergy season has increased across the country due to fewer freezing days. This allows plants to grow and release pollen for a longer period of time each year, exacerbating allergy symptoms for many Americans.

  • Since the 1970s, allergy season has grown longer by an average of 21 extra 'freeze-free' days.

The players

Climate Central

A non-profit science and news organization that analyzes and reports on climate change.

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The takeaway

As climate change continues to impact the environment, the extended allergy season is just one of the many public health challenges communities will face in the coming years. Monitoring these trends and preparing for longer allergy seasons will be crucial for managing the health impacts.