Houston Pollen & Mold Report
Measured counts from the Houston Health Department · Wednesday, September 23, 2026
Pollen: Heavy. Mold: Medium.
This is the complete daily report for the Houston area: every pollen and mold type the City of Houston's monitoring station counted, in grains (or spores) per cubic meter of air. Trees, grass and weeds are added together to give the overall pollen figure; mold is tracked and graded separately on its own, much larger scale. The 60-day trend for each type is charted below, followed by the full species-level breakdown.
Species breakdown
| Trees | Count |
|---|---|
| Maple (Acer) | 0 |
| Alder (Alnus) | 0 |
| Birch (Betula) | 0 |
| Hickory/Pecan (Carya) | 0 |
| Hackberry (Celtis) | 0 |
| Hazelnut (Corylus) | 0 |
| Cedar (Cupressaceae) | 0 |
| Ash (Fraxinus) | 0 |
| Walnut (Juglans) | 0 |
| Sweet Gum (Liquidambar) | 0 |
| Mulberry (Morus) | 0 |
| Pine (Pinaceae) | 0 |
| Sycamore (Platanus) | 0 |
| Cottonwood (Populus) | 0 |
| Oak (Quercus) | 0 |
| Willow (Salix) | 0 |
| Linden (Tilia) | 0 |
| Elm (Ulmus) | 0 |
| Other Tree | 0 |
Grass is reported as a single category total — the Health Department does not break it into individual species.
| Weeds | Count |
|---|---|
| Ragweed (Ambrosia) | 84 |
| Other Weed | 4 |
| Amaranth (Chenopodiaceae/ Amaranthaceae) | 2 |
| Sage (Artemisia) | 0 |
| Aster (Asteraceae) | 0 |
| Sedge (Cyperaceae) | 0 |
| Plantain (Plantago) | 0 |
| Sheep Sorel (Rumex) | 0 |
| Cattail (Typha) | 0 |
| Nettle (Urticaceae) | 0 |
| Mold | Count |
|---|---|
| Ascospores | 4,355 |
| Cladosporium | 2,168 |
| Basidiomycetes | 1,026 |
| Curvularia | 271 |
| Penicillium/Aspergillus | 166 |
| Nigrospora | 133 |
| Cercospora | 127 |
| Periconia | 42 |
| Smuts/Myxomycete | 40 |
| Dreshslera/Helminthosporium | 20 |
| Alternaria | 18 |
| Pithomyces | 12 |
| Rust | 8 |
| Spegazinia | 8 |
| Tetraploa | 8 |
| Oidium/Erysiphe(Powdery Mildew) | 6 |
| Torula | 2 |
| Algae | 0 |
| Epicoccum | 0 |
| Stemphyllium | 0 |
About this report
HoustonPollen.com publishes the Health Department's measured counts — the actual airborne grains identified under a microscope — rather than a computer forecast. New reports are released on weekdays (excluding City of Houston holidays); there is no count on weekends or holidays. For definitions of the level grades and how the counts are collected, see the FAQ.