Taking allergy medicine before you have symptoms is the best way to prevent a miserable allergy season.

Here’s a general rule about allergy seasons:

  • Spring — tree pollen
  • Summer — grass
  • Fall — weeds
  • Year-round — molds

Remember, pollens can travel up to 400 miles in the wind, so watch pollen counts and weather for that distance around you.


 Tips to Prevent and Treat Pollen Allergies

  • Take your medications before you have allergy symptoms.
  • Do outdoor activities in the morning when pollen levels are low.
  • Close your windows, even at night, and use the air conditioning.
  • Wash your hands, body and clothes after being outside. 

View this infographic as a guide to plan your preventive allergy treatment. Watch a local pollen count for more exact timing.


More About Pollens

Grass Pollens

Grasses release pollen in early spring through midsummer. Southern states have grass pollens 10 to 11 months out of the year, and Hawaii has grass pollen year-round. Here are the most common grass allergens:



Did you know that there are about 1,000 mold species that begin to appear in early spring? Mold grows on fallen leaves, compost piles, grasses, grains and produce. In northern climates, frost kills the mold, but warmer climates can have molds year-round. Common mold allergens include:

  • Alternaria — Found indoors and outdoors, thrives on plants, soil, food and indoor air
  • Aspergillus — Found everywhere, including basements, crawl spaces and bedding. This mold thrives on decaying vegetation and causes decay in stored grain and produce
  • Cladosporium hebarum  — Grows on soil and decaying vegetation both indoors and outdoors
  • Penicillium — The green “mildew” that is often seen on items stored in basements. It causes stored grain and produce to rot.

How to Reduce Mold Exposure 


  • Use an exhaust fan, or open a window after showering.
  • Wipe down the damp surfaces after showering.
  • Wash bathrooms with a mold-preventing or mold-killing solution at least once a month.


  • Use an exhaust fan when cooking.
  • Discard spoiled foods immediately.
  • Empty the garbage daily.
  • Empty water pans below self-defrosting refrigerators frequently.


  • Remove moldy stored items.
  • Vent the clothes dryer outside.
  • Remove leaves, clippings and compost from around your house (wear a facemask).
  • Keep the indoor moisture low, less than 50 percent, with an air conditioner or dehumidifier.
  • Avoid using humidifiers, as they can grow and spread mold spores.
  • Clean darkened areas on walls.
  • Repair indoor moisture problems.
  • Limit houseplants (mold spores in the dirt).
  • Don’t store firewood in the house.
  • Wear a mask when doing yardwork and cleaning up moldy areas.
  • Change pillows periodically.
  • Don’t let laundry sit wet overnight.


As winter ends, trees can start releasing pollen. In a warmer winter, the pollen season can last longer than normal. Tree pollen is lightweight, dry and easily blown around in even a light breeze. Common tree allergens are:



By late summer, about 20 percent of Americans are affected by ragweed pollen. Nearly 75 percent are allergic to this weed. Just one plant produces one billion grains of pollen during a single season. Southern states can experience ragweed pollen during the winter months. Allergenic weeds include:


 Reviewed and approved by Ann Hefel, FNP, MS, RN, February 2016