California pollen and allergy seasons
California has a long mild season, with olive and oak in spring, grass into early summer, and lighter weed pollen in the fall.
Twelve month pollen calendar
What is active in September
Cities in California
No tracked cities yet for California.
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 California for ozone, dust, and smoke readings by city.
The California allergy season
Allergy levels in California peak in March, when olive pollen runs highest. The season moves through tree pollen around March, grass in April, weed pollen such as ragweed in August. Levels start to climb around January. The lowest pollen levels of the year arrive in July.
Common questions
When does allergy season start in California?
Pollen levels in California usually begin climbing in January and reach their highest point in March.
What is the worst month for allergies in California?
March is typically the worst month in California, driven by olive pollen.
When does ragweed season end in California?
Ragweed pollen in California usually fades by the end of October, after the first hard frost in colder areas.
When is the best time for allergies in California?
July usually brings the lowest pollen levels of the year in California.