The Kansas year in pollen
Tree pollen in Kansas runs February to May, grass follows May to August, and ragweed starts in early August and holds on until the first frost — typically around October 23.
When does ragweed season end in Kansas?
Ragweed season in Kansas typically ends with the first frost, around October 23.
Ragweed keeps releasing pollen until a freeze kills the plants, which is why the season has no fixed end date — it ends when the cold arrives. More on how frost ends ragweed season.
Tree pollen in Kansas
Tree pollen in Kansas starts in mid-February, and eastern red cedar is usually first out. Mild springs pull the start earlier.
| Tree | Typical season | Heaviest weeks |
|---|---|---|
| Eastern red cedar | February to April | early March to early April |
| Elm | February to April | — |
| Maple | March to April | — |
| Oak | April to May | mid-April to early May |
| Cottonwood | April to May | — |
Grass season
Grass pollen in Kansas runs May to August, heaviest mid-May to early July. Cool-season grasses flower in the first wave; warm-season grasses like Bermuda pick up through summer, which stretches the season. More on grass seasons.
First frost — and ragweed's end — city by city
The first frost sweeps across Kansas over several weeks, and ragweed season ends with it. Based on 30 years of NOAA frost records (1991–2020).
| City | Typical first frost |
|---|---|
| Dodge City | October 20 |
| Topeka | October 23 |
| Wichita | October 29 |
Common questions
When does ragweed season end in Kansas?
Ragweed season in Kansas typically ends with the first frost, around October 23.
When does allergy season end in Kansas?
The last big wave of the Kansas pollen year is ragweed, so the season ends with the first frost, around October 23. Tree pollen is done by May, grass mostly by August.
When does tree pollen start in Kansas?
Tree pollen in Kansas starts in mid-February, and eastern red cedar is usually first out. Mild springs pull the start earlier.
Sources: NOAA U.S. Climate Normals (1991–2020 frost records) · Asthma and Allergy Foundation of America — Ragweed Pollen. Season windows reviewed August 2026.