More than 25 million Americans suffer from the potentially fatal disorder.
Health experts say it is possible for people to manage their asthma in these extreme weather conditions.
High temperatures, thick humidity and increased ozone can set off attacks. Extreme dryness and high humidity require the body to work harder, making it more difficult to breathe. And humidity can bring on mold spores, which can also cause flare-ups.
Doctors say the best ways to lessen the chances of an attack are to use air conditioning, since fans can blow allergens and pollutants like smoke and dirt, and to avoid outdoor activity when possible.