Midwest Tree Pollen Intensifies While the Southeast Stays Broadly Elevated

Tree pollen is still the main burden for allergy sufferers, with the Midwest and Southeast carrying the most widespread elevated conditions. All eight current Midwest stations reached High or Very High tree pollen, and six of eight Southeast stations reached High. South Central tree pollen is less uniform but still active, with four of seven current stations elevated.

The Midwest is the place where tree pressure most clearly moved higher. La Crosse and Omaha both climbed from High to Very High, while the rest of the comparable Midwest stations stayed elevated. The Southeast did not show the same week-over-week jump, but it remains a rough tree region, especially around Cincinnati, Greenville, Marietta, Richmond, Tampa, and Washington.

The Northeast looks less intense than last week, though not completely quiet. Olean stayed at High tree pollen, while Union slipped from High to Moderate; fewer stations reported than last week, so the regional improvement should be read with that narrower coverage in mind. In the West, most reporting stations sat at Moderate or lower for trees, except San Jose (Central), which reached High.

Grass and weeds are still mostly localized. Grass reached elevated levels in Cincinnati and Greenville in the Southeast, Oklahoma City and Tulsa in South Central, and St. Louis in the Midwest. Weeds were quiet in most places, with Las Vegas and Greenville the main elevated pockets. Mold eased in several places and was not broadly elevated, though San Antonio (East) remained at High.

Puerto Rico remains active for tree pollen. Caguas and San Juan both reached High, with San Juan stepping down from last week's Very High peak but still staying elevated. No fresh grass readings showed up there, so the Puerto Rico concern is mainly trees.

Where Allergy Pressure Increased

The clearest worsening was in Midwest tree pollen. Eight of eight current Midwest stations reached elevated tree levels, and two comparable stations moved higher: La Crosse and Omaha both shifted from High to Very High. Appleton, Austin, Chicago, Greenfield, Madison, and St. Louis all stayed at High, so this was not a scattered pattern.

Grass also became more noticeable in a few central stations. Oklahoma City and Tulsa both moved from Moderate to High grass in South Central, and St. Louis moved from Moderate to High in the Midwest. That does not make grass a broad national problem yet, but it is beginning to matter in those pockets.

The Southeast remains one of the harder regions for tree pollen even without broad worsening from last week. All seven comparable Southeast tree stations held their prior severity level, and six current stations remained elevated. Cincinnati, Greenville, Marietta, Richmond, Tampa, and Washington all stayed at High.

The West had a more mixed pattern. Tree pollen eased at Eugene, Riverton, and Seattle, while San Jose (Central) appeared as a current High tree station without a comparable prior-week reading. Las Vegas was the main weed increase, moving from Moderate to High.

Main Drivers

Mulberry, birch, and oak were the main Midwest tree drivers. Mulberry reached elevated levels at four Midwest stations, birch at three, and oak at three; both La Crosse and Omaha moved into the top severity band as the region intensified.

Oak remained the leading Southeast tree allergen, reaching elevated levels at five stations. Mulberry also contributed at two stations, but the broader Southeast burden was still mostly an oak story. In South Central, hickory/pecan and oak were the main elevated tree allergens.

Outside trees, other kinds of pollen were much more localized. Las Vegas' weed issue was tied to ragweed, while San Antonio's mold reading came from a broader identified-fungi grouping rather than a widespread regional mold surge.

In Puerto Rico, the active tree readings came from a general identified-tree grouping rather than a more specific named allergen. That still matters for sufferers there because both reporting stations reached High.

Weather Context

Cooler weather in the Northeast coincided with the drop from last week's stronger tree pattern, which fits the lower current tree severity there. In the West, precipitation was uneven: rain showed up across several coastal and inland stations, while snow was concentrated in Alaska, Missoula, and a few interior stations. Most tree stations there were no higher than Moderate, aside from San Jose (Central).

The Midwest cooled and dried out compared with last week, but tree pollen still intensified, so weather does not offer a simple relief story there. In the Southeast, conditions stayed warm enough for tree pollen to remain broadly active even as the region cooled from last week. South Central was cooler but still wet, which lined up with a mixed picture: tree pollen stayed active in several stations while grass became more noticeable in Oklahoma.