April 2026
Some types of weather can trigger asthma symptoms, including high heat, cold, humidity, and sudden weather changes.
Cold, dry air
Cold and/or dry air can cause your airways to narrow. Cold air can be especially problematic if you have exercise-induced asthma. If you struggle with exercising in cold, dry air, move your fitness routine indoors.
Also, be on the lookout for indirect impacts of the weather on your asthma. For example, do you run a wood stove or fireplace when it’s cold? It may be the smoke that’s triggering asthma. Or do you have forced hot air heating? It may be stirring up dust.
Hot, humid air
Hot, humid weather doesn’t typically impact your airways directly. Instead, it causes things that trigger asthma.
Hot, humid air can be a problem for people with allergic asthma (that is, asthma triggered by allergens). Humid air, especially when it’s hot, fuels the growth of dust mites and mold — two common allergens. And pollen (another common allergic asthma trigger) tends to be more abundant during hot weather.
In addition, air pollution and ground-level ozone (two other asthma triggers) tend to worsen when it’s hot and sunny because of how pollution responds to heat and sunlight.
Rain and thunderstorms
The sudden heavy rain that sometimes accompanies thunderstorms can break apart pollen grains, making them smaller, easier to transport, and easier to inhale. This can cause an asthma flare-up if you’re allergic to pollen.
