Seasonal allergies—a nuisance that seems to start as soon as the trees have leaves. Outside pollens change and allergy and asthma symptoms start, but did you ever notice that allergies are better on some days and worse on others. Outdoor pollens are flying everywhere and are hard to avoid, but depending on the season, they are all different. Allergy season is not just in the spring like some think. Depending on what pollen is being released into the air, it can occur at different times per year.

So what is pollen? The official definition is “a mass of microspores in a seed plant appearing usually as fine dust.” If you look closely at outside furniture, car windshields or even your mailbox, you can see this layering of fine dust.

Seed bearing plants produce pollen and it is carried by wind, insects or animals. As the wind picks up the pollen, it can trigger allergy or asthma symptoms. There are three different classifications of plants that produce these pollens. These plants all release at different times per day and year.

We start the year with release of tree pollen. Starting March to mid-May, trees release pollen spores most often between noon and 6 p.m. With trees like elm, willow, oak, hickory, maple, cedar, ash, beech and birch causing the most asthma symptoms.

As we head into summer, mid-May to July, grass pollens take over. Starting early in the morning and throughout the day, grass releases its pollens into the air. If the grass is wet, it will delay its pollen release until the moisture has evaporated.

Starting the end of June into September, weeds have the longest time frame to release pollen into the air. The most common culprit is ragweed. It releases pollen from sunrise until about 9 a.m. Other weeds known to release allergic pollen are thistle, sagebrush and mugwort.

Like most of us, seed bearing plants prefer warm, sunny days to release their pollens into the air and stay more dormant during cool, rainy days. Pollen will go up into the atmosphere during the day, and as the air cools during sunset it will fall, reaching the ground between 8 and 10 p.m. This means that people who are sensitive to outdoor allergens should try to stay inside midday to afternoon when pollen count is highest.

Medications are the first defense we think of when we suffer from allergy or asthma symptoms caused by these pollens. We can add to this defense by understanding which pollen causes our symptoms, therefore, being able to reduce, avoid or eliminate it.