pollendates

When does pollen season start — and end?

Tree pollen, grass, and ragweed each run on their own calendar, and every state runs its own version of it. Pick your state for the year in pollen: when each season typically starts, when it peaks, and — the question that matters by September — when it finally ends.

Tree pollen
Grass
Ragweed
The national spread. Southern states start earlier and run longer; northern ones compress the whole year into fewer months. Your state's page narrows every bar.

The one date worth knowing: first frost

Ragweed — the sneeze factory of late summer — doesn't wind down on a schedule. It keeps going until the first frost kills it. That makes "when does ragweed season end" a weather question with a real answer: your area's typical first-frost date, from 30 years of NOAA records. How frost ends ragweed season.

Your state's year in pollen

By allergen