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Spring allergy season arrives early in Western WA as tree, blossom pollen rises

Mar 31, 2026, 5:00 AM | Updated: 2:43 pm

allergy season...

A bicycle rider zips past flowering plants. (Photo: Chris Hondros, Getty Images)

(Photo: Chris Hondros, Getty Images)

Are you an allergy sufferer? You likely already know allergy season has arrived with sniffles, runny noses, and red, itchy eyes.

The spring season is getting underway, and the sun will make more and more appearances in the weeks ahead as temperatures warm up. Trees and plants are noticing spring has arrived and awakening. But for allergy sufferers, spring means allergy season is here!

If it seems allergy season is starting earlier and earlier, you would be correct. Studies have shown that since the 1950s, summer is now more than three weeks longer worldwide, while the fall, winter, and spring seasons have all become shorter.

In recent years, it feels like summer in Western Washington has gotten underway earlier. For instance, just a few years ago, in May 2023, temperatures soared up to near 90 degrees in the middle of the month.

Allergy offenders

Early in the allergy season, trees are the greatest offender as they awaken from their winter slumber. Leaves and blossoms are sprouting, sending their pollen into the air and finding noses. The University of Washington (UW) cherry trees are in full bloom, quite picturesque, yet for those with allergies, a real struggle.

The tree pollen season is just getting underway. At this time, the most offending trees are hazelnut and birch. Cedar and junipers are also getting started. Cottonwood, Poplar, Alder, Willow, and Maple trees are next at bat. Later in April and May, Sycamore, Ash, and Oak trees will contribute their own pollen.

With longer days, more sunshine, and warmer weather, grasses and weeds will then replace tree pollen and offer their own pollen later this spring and heading into summer.

The Western WA advantage

Even though many suffer from allergies during spring and summer, Western Washington has a significant advantage when it comes to seasonal allergies – rain. Rain washes away pollen, cleansing the air and offering great relief to allergy sufferers.

The 2026 Asthma and Allergy Foundation Report reviewed data from 100 U.S. cities, and three of them are from Washington. Spokane is ranked ninth in the country, Portland/Vancouver sits at No. 38, and the Seattle metro area moved up to No. 45 from No. 88 just two years ago.

Boise, Idaho, tops the list at No. 1 in the nation, while San Diego, California, is just behind at No. 2. Most of the top 20 cities were all from the central plains to the eastern seaboard.

Tracking pollen counts

When Western Washington weather gets warmer and drier, pollen counts rise. The Northwest Asthma and Allergy Center posts daily pollen counts, including the most common offending pollen contributors. The next rainy or even windy day will reduce pollen in the air and offer allergy relief.

Dr. Jan Agosti, an infectious disease specialist affiliated with UW Medicine, offers an idea for allergy sufferers when pollen counts rise.

“Face masks. It’s now socially acceptable to wear them, and while high filtered masks are best, even plain old cloth ones help,” Agosti noted. “Sunglasses and eyeglasses help, too — anything that keeps it out of your nose and eyes.”

Ted Buehner is the KIRO Newsradio meteorologist. Follow him on X and Bluesky. Read more of his stories here.

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Spring allergy season arrives early in Western WA as tree, blossom pollen rises