The states with the worst seasonal allergies cluster heavily across the South, the southern Plains, and parts of the Midwest. Kansas, Virginia, South Carolina, Texas, Oklahoma, Iowa, North Carolina, and Arkansas all contain cities that rank among the ten most challenging places in the country for allergy sufferers, based on the Asthma and Allergy Foundation of America’s 2024 Allergy Capitals report. These rankings factor in pollen counts, allergy medication use, and the number of allergy specialists available per patient.
The 10 Worst Cities for Allergies in 2024
The AAFA ranks metropolitan areas rather than states, but the pattern is clear. Here are the top 10 most challenging cities:
- Wichita, Kansas
- Virginia Beach, Virginia
- Greenville, South Carolina
- Dallas, Texas
- Oklahoma City, Oklahoma
- Tulsa, Oklahoma
- Richmond, Virginia
- Des Moines, Iowa
- Raleigh, North Carolina
- Fayetteville, Arkansas
Oklahoma is the only state with two cities in the top ten. Virginia also places two: Virginia Beach and Richmond. Texas, while only landing one city in the top ten, is consistently near the top of the list year over year because its warm climate drives an exceptionally long pollen season.
Why the South Dominates the Rankings
Geography is the biggest factor. Pollen seasons start earlier and last longer the farther south you go. Oak pollen season, for example, begins around February 11 in Houston but doesn’t kick off until May 2 in Rochester, New York. That nearly three-month gap means southern residents are breathing in tree pollen while people in the Northeast are still dealing with winter.
Grass pollen follows the same pattern. While it’s known as a summer allergen, the grass pollen season can stretch from March all the way to November in southern latitudes. In parts of Texas, pollen concentrations dip only briefly in July before a third wave hits from mid-September through October, driven by ragweed, fall-pollinating elm, and other weed pollen. Some parts of the South now experience pollen year-round, with trees producing pollen as early as December or January.
Ragweed compounds the problem in fall. Unlike tree pollen, ragweed season starts at roughly the same time regardless of latitude. But it ends later in the South because the season’s cutoff is the first hard frost. In states like Texas, Oklahoma, and Arkansas, that frost arrives weeks or even months later than in the northern Midwest, extending ragweed misery well into November.
The Midwest and Ohio Valley
States like Iowa, Ohio, and Kentucky might not have the longest allergy seasons, but their peak periods hit hard. In Ohio, tree pollen peaks from February through May, grass pollen dominates in May and June (with ryegrass and bluegrass as the biggest culprits), and ragweed takes over from August through November. That’s essentially nine months of overlapping pollen exposure with only a brief winter reprieve.
The Midwest is particularly rough for ragweed. It’s one of the most common fall allergens across the entire region, and the flat, open terrain of the Great Plains allows pollen to travel hundreds of miles on the wind. Cities like Wichita and Des Moines sit in the middle of vast agricultural landscapes where ragweed and grass pollen have few natural barriers.
How Cities Make Allergies Worse
Living in a metro area within these states can intensify your symptoms beyond what the regional pollen count suggests. Urban areas run warmer than the surrounding countryside due to the heat absorbed and radiated by pavement, buildings, and infrastructure. That extra warmth causes trees to flower earlier in cities than in nearby rural areas. In Detroit, researchers found that a 6°C temperature difference across the metro area shifted peak oak flowering by over three weeks, from April 20 in warmer neighborhoods to May 13 in cooler outlying zones.
This means pollen exposure in a city center can start days or weeks before regional pollen monitoring stations detect elevated levels. It also means the pollen season effectively stretches longer in urban environments, as trees in warmer pockets bloom first and trees in cooler pockets bloom last, creating a rolling wave of pollen across the city.
Allergy Seasons Are Getting Longer
If allergies feel worse than they used to, you’re not imagining it. Rising temperatures over the past several decades have pushed pollen seasons earlier and stretched them longer. For some plant families, the season has shifted by one to three weeks earlier than it started 30 years ago. Oak pollen season now begins 5 to 13 days sooner, and grass pollen season starts 8 to 25 days earlier, depending on the region.
The duration of the season is expanding too. Hazel pollen season has lengthened by 10 to 29 days over three decades, an increase of 21 to 104 percent. Nettle and hemp family pollen seasons have grown by 8 to 37 days. These changes are driven by warmer springs that trigger earlier flowering and warmer autumns that delay the first frost, giving late-season allergens like ragweed more time to produce pollen.
The states that already ranked worst for allergies are feeling this shift most acutely. Southern and Plains states with long baseline pollen seasons are seeing those seasons stretch even further, while Midwestern states are losing the short winter window that once gave allergy sufferers a break.
States With the Mildest Allergy Seasons
If you’re considering a move, the West Coast and Mountain West tend to fare better. Arid climates with less vegetation produce lower pollen counts overall, and coastal areas benefit from onshore winds that push pollen inland rather than concentrating it. Higher elevations also mean shorter growing seasons and fewer allergenic plant species. That said, no state is completely allergy-free, and local factors like irrigation, urban landscaping choices, and proximity to agricultural land can create pockets of high pollen even in otherwise mild regions.