Houston Pollen Trends & Season
Measured counts from the Houston Health Department · Thursday, July 23, 2026
How does today compare to the rest of the season — and to past years? These charts use the Health Department's measured daily counts to show the last 60 reporting days, the months when pollen is typically worst in Houston, and how recent years stack up.
Last 60 reporting days
Total pollen (trees + grass + weeds), grains/m³ · May 27 – Jul 23
Outdoor mold, spores/m³ · May 27 – Jul 23
When is pollen worst in Houston?
Averaged across 5 years of measured data, total pollen in Houston is typically highest in March. The spring tree-pollen surge dominates the annual peak, with a second, smaller bump from weeds (mainly ragweed) in the fall. Mold, driven by heat and humidity, stays elevated through much of the warm season.
Average measured pollen by month (grains/m³), all years combined.
Year over year
Each year's peak single-day count and daily average, so you can see whether this season is running heavier or lighter than usual. 2026 is still in progress.
| Year | Peak day (pollen) | Daily average | Days reported |
|---|---|---|---|
| 2022 | 12,570 | 413 | 362 |
| 2023 | 4,740 | 332 | 362 |
| 2024 | 3,524 | 272 | 365 |
| 2025 | 9,509 | 364 | 365 |
| 2026 (YTD) | 4,304 | 348 | 204 |
"Peak day" is the single highest total-pollen reading that year.