Tree Pollen Stayed Intense Nationwide, as Southeast Grass Season Picked Up

Tree pollen remained the main burden for allergy sufferers. The heaviest pressure was in Texas and Oklahoma, where seven of eight reporting South Central stations were still High or Very High, with the sharpest strain around Oklahoma City and San Antonio. The Southeast looked nearly as difficult, with seven of eight stations also elevated, led by Tampa and the Washington, D.C., suburbs. The Midwest stayed firmly in season as well, even though a few Wisconsin sites trended lower from last week.

Outside of trees, the picture was much more localized. Grass became more noticeable in the Southeast, led by Birmingham, Greenville, and Richmond. Elsewhere, grass was mostly a spot problem rather than a broad one, with Portland the main Western exception. Weeds stayed quiet outside a few isolated pockets, and mold never built into a broad national story.

Some regions did look meaningfully less intense than last week. The Northeast was no longer broadly locked into a rough tree pattern: only Olean stayed in the upper tier, while Armonk and New York City slipped back and Union, New Jersey fell to Low. The West was also mixed rather than uniformly heavy on trees: Eugene, Portland, and Reno stayed at High, Missoula newly reached High, and Las Vegas, Riverton, and Scottsdale dropped from High to Moderate.

Puerto Rico still deserves mention. Where stations reported, San Juan and Caguas stayed elevated on trees, San Juan moved into the upper grass band, and Mayaguez continued to post elevated mold.

Where Allergy Pressure Increased

The clearest worsening was in Southern grass pollen rather than in the main tree belt. Birmingham entered at Very High, Richmond climbed from Moderate to High, and Marietta moved up a band. That left three Southeast stations in the top two grass bands, up from one of five comparable stations last week.

There were also a few meaningful upticks outside the Southeast. Chicago moved from Moderate to High on trees, keeping the Midwest firmly active even as Madison and La Crosse stepped back slightly. In the West, Portland jumped from Low to High on grass, and Missoula newly reached High on trees, even as several desert and Intermountain tree stations eased to Moderate.

The South Central region did not worsen in the way sufferers usually feel most sharply, because the main tree burden was already elevated and stayed there. But early-season categories did get more noticeable: Austin, San Antonio West, and Tulsa all moved from Low to Moderate on grass, while Austin and Houston both moved from Low to Moderate on mold.

Main Drivers

Oak was the main tree driver in the places carrying the biggest burden. It was the most widespread elevated tree allergen across Texas, Oklahoma, and much of the Southeast, and it remained the clearest reason those regions still felt rough.

The rest of the tree story was more regional. Mulberry stayed prominent in both the South Central and Southeast, while pine family pollen showed up repeatedly across the Southeast. In the Midwest, juniper and cedar carried more of the tree story than any other named allergen. In the West, no single tree allergen took over the whole region; ash, oak, and poplar/cottonwood/aspen each showed up across smaller pockets.

Weather Context

Weather shifts were mixed. The Southeast turned a bit cooler and wetter than last week, but not enough to shut tree season down, and grass still pushed higher in Alabama and Virginia. South Central weather also cooled off, which coincided more with trees holding at already elevated levels than with any real relief.

The West turned warmer and much drier, and that coincided with Portland's grass jump and a new elevated tree reading in Missoula, even though several Western tree stations eased. Puerto Rico turned slightly warmer and drier, which coincided with San Juan's grass increase while tree pollen remained elevated.