Midwest Tree Pollen Stays Rough as Puerto Rico Reaches Very High

Tree pollen is still the biggest allergy problem for many readers, especially in the Midwest, Puerto Rico, and parts of the South Central region. The Midwest remains the broadest mainland trouble spot: five of seven current stations reached High or Very High tree pollen, with La Crosse still in the top band and Chicago, Greenfield, Madison, and Omaha also elevated.

Puerto Rico now has the most intense tree pattern. Caguas and San Juan both climbed from High to Very High, while mold stayed low to moderate there.

South Central conditions are uneven but still active. Tree pollen remained elevated in Oklahoma City, San Antonio (West), Tulsa, and Waco (Woodway South), even as Houston and San Antonio (East) dropped from last week's elevated levels. Grass is also becoming harder to ignore, with Oklahoma City, Tulsa, and Waco (Woodway South) reaching High.

Elsewhere, the Southeast is less broadly intense for trees but not quiet, with Cincinnati and Greenville still elevated for both tree pollen and grass. The Northeast had a localized tree uptick at Lebanon and Union, while the West was mostly calmer as San Jose tree pollen and Las Vegas weeds dropped out of elevated territory.

Where Allergy Pressure Increased

Puerto Rico had the clearest worsening: two of two comparable stations moved from High to Very High tree pollen. For sufferers in Caguas and San Juan, that is a real step up in intensity.

The Northeast increase was smaller and more localized. Lebanon and Union climbed from Moderate to High tree pollen, while Olean moved the other way, from High to Moderate.

Several mainland metros also picked up new non-tree pressure. In South Central, grass reached elevated levels at three of eight current stations, and mold rose to High in Austin and Oklahoma City. In the Midwest, Chicago grass climbed to High, and Chicago and St. Louis mold both moved from Low to High. Tree pollen there stayed broadly elevated, but it did not worsen overall: three comparable Midwest stations moved down, four held steady, and none moved higher.

Main Drivers

Midwest tree trouble came from several spring trees rather than one allergen alone. Oak, birch, maple/box elder, and mulberry each reached elevated levels at multiple stations; oak was the only one to hit Very High, at La Crosse.

In South Central, hickory/pecan and oak were the main named tree contributors. The mold increase was tied to unidentified fungi at Austin and Cladosporium at Oklahoma City. In the Southeast, the remaining elevated tree readings were narrower, centered on Cincinnati and Greenville, where pine-family pollen and oak showed up alongside elevated grass.

Weather Context

Rain lined up with some tree-pollen relief in the Southeast, including lower readings at Richmond, Tampa, Washington, and Marietta. Cincinnati and Greenville were the important exceptions, staying elevated despite the broader softening.

South Central stayed warm and wet, a setup that matched the mixed reader experience there: active tree pollen in Oklahoma and parts of Texas, plus more grass and mold. In the Midwest, cooler, rainy weather did not bring broad relief because tree pollen stayed elevated at most current stations and mold rose in Chicago and St. Louis. Cooler, wetter conditions in the West coincided with a quieter pollen picture.