Why are Louisville’s allergies so bad?

How plant life and geology make for a truly sneezy spring in Derby City.

A field of bluegrass, topped with brown seeds. A bare ridge in the distance is lined with trees.

Kentucky Bluegrass may look pretty, but it’s also a major allergen.

Photo by Matt Lavin via Wikimedia Commons

You’ve probably heard it before — Louisville is the worst for allergies. But why does Derby City get that reputation? And is it deserved? Let’s take a look at some facts — and myths — about Louisville’s allergens.

Are Louisville allergies getting worse?

In 2025, Derby City ranked No. 69 on the Asthma and Allergy Foundation of America’s allergy capitals of the US. While that’s nothing to sneeze at, it’s a far cry from where Louisville placed a decade ago.

In 2014, Louisville was the No. 1 worst place for allergies in the entire country. LOU stayed in the top 10 until 2019, but has spent the 2020s much lower on the list.

  • No. 20 in 2021
  • No. 43 in 2022
  • No. 89 in 2023
  • No. 82 in 2024

So are allergies getting better in Louisville? Not necessarily. Nationwide, climate change has led to longer pollen seasons + increased pollen production. So Louisville may not be getting better — it might just have more competition.

Why are Louisville’s allergies so bad?

One of the main factors contributing to Louisville’s severe allergy season is its geography. The Ohio River Valley keeps pollen trapped + recycled, rather than letting it disperse. Thanks to the river, the valley also stays quite humid, which promotes the growth of mold.

How can I improve my allergies?

UofL Health has a few tips to help keep your allergies at bay:

  • Wash your sheets in hot water
  • Keep windows closed at home + in the car
  • Use a nasal saline rinse to flush out allergens
  • Wear a mask when mowing or gardening
  • Consult your doctor about a proper medication — this year, one of the contributing factors to Louisville’s ranking as an allergy capital was below-average use of over-the-counter sinus and allergy medication.
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