Scientists at the University of Michigan studied pediatric emergency room visits in Detroit. They found the number of visits for asthma attacks rose when humidity levels increased or decreased.
Rising temperatures also sent more children to the emergency room with asthma symptoms.
It's believed that the humidity and temperature shifts may aggravate inflammation in the airways of the lungs.
Factors such as pollution and pollen counts can also exacerbate asthma symptoms.
"It's been long known that in people with asthma who aren't controlled," said Dr. Richard Gower, president of American College of Allergy, Asthma and Immunology. "Just swallowing cold or hot liquid can set off an asthma attack. The temperature sets off a bronchial spasm. We know that a change in temperature, down or up can set it off."
The research is published in the September issue of The Annals of Allergy, Asthma, & Immunology.