U.S. RegionsNo matter the month, it's always allergy season somewhere in the United States. That's because the trees, grasses and weeds that cause trouble for allergy sufferers all have their own bloom times, which vary according to region.
Pollen season begins earlier in warmer climates than in cooler climates and typically ends after the first hard freeze. Trees generally are the first to pollinate. Grasses are next, with weeds being the last to do so. Seasonal weather patterns play a role on the amount of pollen that plants produce in a growing season. In addition, daily weather conditions also have an effect on the amount of aggravating wind-dispersed pollens in the air. Blustery, windy days stir up pollen. If your allergies are aggravated by pollen, try to avoid being outdoors in these types of conditions. On the flipside, windless and rainy days seem to lower pollen counts.
This pollen zone map is divided into regions within the continental United States. Pollen counts vary from region to region, so click on the region where you live to determine when the different types of pollen are at their worst.