POLLEN COUNT 1,000 800 600 400 200 0 2013 TODAY 2012 2014 Average (typically the third week of April) JANUARY FEBRUARY MARCH APRIL MAY JUNE JANUARY FEBRUARY MARCH APRIL MAY JUNE Alder Red cedar Maple POLLEN SEASON Average weekof peakpollen Elm Willow Pine Poplar (Cottonwood) Beech Sweetgum Oak Sycamore Ash Mulberry Hickory A long winter can delaypeak pollen weeks. Later-blooming trees are less affected by a long winter. This year’s peak allergy season is hard to predict, but a good guess is the third week in April, which is average for this area, said microbiologist Susan Kosisky, author of a study of pollen trends in the D.C. area. Despite low pollen counts so far, a spike is likely to arrive soon, in part because oaks account for about 50 percent of area pollen and are little affected by a long, cold winter.

SOURCE: Susan Kosisky of the U.S. Army Allergen Extract Lab; “Pollen aeroallergens in the Washington, D.C., metropolitan area: A 10-year volumetric survey (1998-2007)” by Kosisky, et al.