The reason is probably plant pollen, which can cause allergies and irritate your airways. When you are exposed to pollen, your body responds by creating a defense called antibodies, which attach themselves to special cells in the nose and airways called mast cells. In turn, the mast cells produce and release chemicals that cause nasal allergy symptoms like sneezing and a stuffy, runny, itchy nose. Tree pollens cause problems in early spring, while grass pollens strike in late spring and early summer. Weed pollens will cause flare-ups in late summer.
Seasons begin at different times in the United States.
For example, weed pollen strikes the North-Northeast from June to October. But the Pacific Northwest has a high weed pollen count from April to December. That's why it's so important to learn your area's seasonal pattern. Weather and time of day also affect nasal allergy symptoms. Ragweed releases its pollen in the morning, and a strong wind may carry it right through an open window.