San Antonio, TX Pollen Levels Today

San Antonio sits at the edge of the Texas Hill Country, and its warm, humid subtropical climate combined with a long growing season makes it one of the most challenging allergy cities in the United States. The area is especially infamous for its winter "cedar fever" outbreak, when mountain cedar (Ashe juniper) releases massive pollen loads from mid-December through February.

As cedar subsides, a second tree wave takes over in spring, with oak, ash, elm, pecan, mulberry, and hackberry peaking from February through April; oak pollen in particular can blanket the city in yellow dust. Grass pollen follows, dominating from late April into summer and often lingering through early fall, driven largely by Bermuda, Johnson, and Timothy grasses.

Weed season arrives in late summer and fall, with ragweed leading the charge from August through October, alongside pigweed, careless weed, and sagebrush. Overlap is common—late-spring tree and grass pollen frequently coincide, intensifying symptoms.

Beyond pollen, San Antonio's humidity fuels year-round mold spores (especially Alternaria and Cladosporium), while dust, cedar elm debris, and occasional Saharan dust plumes add to the burden. Overall, the city's allergy profile is defined by its severe cedar season, diverse tree and weed exposure, and nearly year-round symptom potential.