New Hampshire pollen and allergy seasons
New Hampshire has a late spring tree season, grass in early summer, and a moderate ragweed season in the fall.
Twelve month pollen calendar
What is active in September
Cities in New Hampshire
No tracked cities yet for New Hampshire.
Today and worst today come from live readings where available. Typical shows the usual level for this month from the seasonal profile.
Pollen is only half of what's in the air. See today's air quality in New Hampshire for ozone, dust, and smoke readings by city.
The New Hampshire allergy season
Allergy levels in New Hampshire peak in May, when birch pollen runs highest. The season moves through tree pollen around May, grass in June, weed pollen such as ragweed in September. Levels start to climb around April. The lowest pollen levels of the year arrive in January.
Common questions
When does allergy season start in New Hampshire?
Pollen levels in New Hampshire usually begin climbing in April and reach their highest point in May.
What is the worst month for allergies in New Hampshire?
May is typically the worst month in New Hampshire, driven by birch pollen.
When does ragweed season end in New Hampshire?
Ragweed pollen in New Hampshire usually fades by the end of October, after the first hard frost in colder areas.
When is the best time for allergies in New Hampshire?
January usually brings the lowest pollen levels of the year in New Hampshire.