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Allergy season begins, pollen counts on the rise in Portland

Maple trees starting to bloom on the first day of spring in Portland as seen by KOIN 6 Meteorologist Josh Cozart

PORTLAND, Ore. (KOIN) — Spring has sprung as warmer and drier weather swings Portland into the 2023 allergy season.

Monday’s light rain showers helped keep Portland’s pollen count low for the first official day of spring. However, low pollen counts won’t last as temperatures begin to warm.

Those who suffer from tree pollen like juniper, alder, and poplar are feeling it the most in Portland.

KOIN 6 Meteorologist Josh Cozart shares Portland’s pollen count forecast through the week’s end

Tree pollen continues to decrease through the growing season after grasses win the top spot for worse pollen counts come May. Weeds don’t become aggressive until later in the growing season.

Average pollen count trend through allergy season in Portland

Allergy season has only now begun. May and June typically brings some of the highest pollen counts due to the grasses found throughout the Willamette Valley.

It’s no surprise Portland’s seen an increase in pollen activity recently. Dry and warm weather over the last few days have helped send trees, shrubs, and flowers into bloom.

Recorded temperatures in Portland as of March 19, 2023

Portland saw temperatures climb into the 60s for four consecutive days last week. The lack of rain remains in the Portland metro forecast through the middle of the week. That will bring back higher pollen counts as earlier as Tuesday.

Higher temperatures mid-week will help fuel the climbing pollen numbers before cooler and wetter weather returns by the end of the week.