Common Pollens and Allergens in Seattle and Western Washington

Four young women jogging together along coastal park, Seattle, Washington, USA

Michael Hanson/Aurora Photos/Getty Images 

Seattle and Tacoma allergy sufferers can have it pretty rough during the local allergy season, which can start as soon as mid-January and run clear through the end of summer in some years. If you've never had seasonal allergies, count yourself among the fortunate. If you have, maybe you know a bit about what you react to, or maybe you have no idea, but understanding what allergens in the area can at least help you anticipate when your season is around the corner.

With the abundant trees, grass, weeds, and other greenery in the region, there is no shortage of pollen in the air. On top of that, dust, mold, air pollution, and other allergens add another dimension to the Seattle allergy scene.

But which allergens are most common? Are there any particular allergens that are worse than others? The Northwest Asthma & Allergy Center is a fantastic resource to learn a bit more about what exactly is making you sneeze. Below is a question-and-answer session about what allergy sufferers can expect in the area.

Get your tissues ready!

Common Allergens Affecting the Most People in the Seattle Area

According to Dr. Audrey Park of the Northwest Asthma & Allergy Center, "There are several allergens that affect many allergy sufferers. The dust mite is one of the most common perennial allergens, whereas Alder and grasses are the main seasonal allergens in Seattle. Of course, allergy to pet dander is also quite prevalent, although not obviously unique to Seattle. "

When Is Peak Allergy Season?

"With our interesting convergence zone and unpredictable weather, it is difficult to generalize the peak allergy season," explained Dr. Park, "for how cold and persistent our winter is, clearly factors into the intensity of the spring tree pollens. The most trouble often comes when trees pollinate early and we are caught still thinking it is winter so we have not started our seasonal allergy medications yet. Certainly, there are variations among individuals with allergies, but overall late March and late June are the peak pollen months when one can be most symptomatic."

Are There Grasses to Avoid Planting for Those Allergic to Grasses?

Most grass species are cross-reactive to one another, so usually if you are allergic to one type of grass pollen, you usually react to the others, said Dr. Park. "Therefore, unfortunately for grass-allergic individuals, there is not a specific grass to avoid, as most types will cause symptoms."

What Weeds Most Commonly Cause Allergies in Western Washington?

"English plantain is probably the most plentiful in Western Washington," according to Dr. Park. "Actually, we are fairly fortunate not to have many weed allergens here. In Eastern Washington, ragweed, sagebrush, pigweed, and Kochia can pollinate while grasses are still actively pollinating, causing significant issues for those with allergies."

Pacific Northwest Afternoon
Intergalactic Design Studio/Getty Images 

Common Sources of Pollen

There are a number of allergens that make their appearance throughout the spring and summer in Seattle. Even if you don't have an allergy doctor on standby, you can get an idea of what might be affecting you if you keep an eye on pollen forecasts during your peak allergies. Here's a list of when the most common pollen takes to the air around Western Washington:

  • Maple: March to May
  • Hazelnut: Mid-January to mid-March
  • Cedar/Juniper: February to June
  • Alder: Late-February to mid-May
  • Elm: Mid-February to early May
  • Birch: Mid-March to mid-April
  • Cottonwood/Poplar: March to April
  • Oak: Late April to early June
  • Ash: Mid-April to May
  • Grasses: Mid-April to September, peak in June
  • Weeds: Mid-May to September
Was this page helpful?