
Live oak
Quercus virginiana
Moderate today, mostly grass pollen.
Last updated September 30, 2026
Grass pollen is the main driver of today's conditions in Pasadena, sitting at a moderate level that may be noticeable if you tend to be sensitive to it. Tree and weed pollen are both low and should be easy to manage for most people. Overall, this adds up to a moderate day, with grass being the one to watch if you typically react to it. Looking ahead, grass pollen is expected to ease slightly over the next couple of days before ticking back up toward the end of the five-day stretch, while tree and weed pollen should remain low throughout. This lines up with the seasonal pattern for late September, when tree pollen from species like Liquidambar, Celtis, oak, elm, and willow is largely dormant, and attention shifts more toward lingering grasses and the tail end of the weed and ragweed season. No dramatic changes are expected in the near term, so conditions should stay in a similar, manageable range through the week.
Every dot is a tree near Pasadena, colored by how allergenic it is. Click one for its details, and zoom in for a closer look.
The local tree genera behind today's pollen near Pasadena. Each bar is that genus's share of the tree pollen.
111 pollen-relevant trees nearby drive today's tree-pollen reading.
Get to know the tree types growing around Pasadena: what each looks like, how allergenic it is, and when it blooms.

Live oak
Quercus virginiana

Common hackberry
Celtis occidentalis

Pecan
Carya illinoinensis

Arizona ash
Fraxinus velutina

Water oak
Quercus nigra

Willow oak
Quercus phellos

Loblolly pine
Pinus taeda

Bradford pear
Pyrus calleryana

American elm
Ulmus americana

Chinese elm
Ulmus parvifolia

Cedar elm
Ulmus crassifolia

Juniper
Juniperus chinensis

American sycamore
Platanus occidentalis

Mulberry
Morus

Catalpa
Catalpa

Nuttall oak
Quercus nuttallii