The Tri-Cities year in pollen

Pollen seasons in Tri-Cities: tree pollen January to May, grass April to September, and ragweed from early August until the first frost, around October 24.

First frost lands around October 24 in Tri-Cities — about 10 days earlier than Tennessee overall — which shifts when ragweed season ends here.

Tree pollen
Grass
Ragweed
Ragweed's bar ends at the typical first frost — around October 24.

When does ragweed season end in Tri-Cities?

Ragweed season in Tri-Cities typically ends with the first frost, around October 24. Some years it comes as early as October 18, some as late as October 29.

A light frost around October 24 knocks the season down; the hard freeze that finishes it usually follows by November 1. Based on 30 years of NOAA frost records (1991–2020).

The rest of the Tri-Cities pollen year

AllergenTypical season
Oak March to May
Pine March to May
Eastern red cedar January to March
Maple February to April
Birch March to April
Hickory April to May
Grass April to September

Season-by-season detail is on the Tennessee page.

Nearby calendars

Frost dates for Tri-Cities come from the Bristol Tri City Airport weather station's 30-year records. Season windows reviewed August 2026.