Seasonal allergies tend to worsen during certain times of the year due to the increased presence of specific allergens in the environment. For example, in the spring, trees release large amounts of pollen into the air, triggering allergic reactions in susceptible individuals. Pollen levels are typically highest in the early morning and late afternoon, and they can vary depending on geographic location, weather conditions, and the types of trees in the area. During the summer, grasses, such as Timothy and Bermuda grass, are the primary pollen producers, contributing to another peak in allergic reactions. Fall allergens like ragweed pollen become more problematic during the late summer and fall months, often causing severe allergy symptoms in many people.

In addition to pollen, environmental conditions such as temperature, humidity, and rainfall can affect the severity of allergy seasons. Warmer temperatures can increase the production of pollen, while humidity can encourage the growth of mold, another common allergen. Rainfall can also have a dual effect: while it can wash pollen out of the air temporarily, it can promote mold growth in certain areas, especially in damp or poorly ventilated environments. Climate change has contributed to longer and more intense allergy seasons, with some regions experiencing higher levels of allergens for extended periods of time. This means that people with seasonal allergies may find that their symptoms last longer or become more severe than in previous years.