The study found that about 51 percent of the participants did have a weather trigger, though about 62 percent thought that they were sensitive to weather. The most common weather trigger was extremely hot or cold weather, the second was an extreme of atmospheric pressure such as humidity or dryness, and the third factor was any major change in the weather over a two-day period. Almost 40 percent of all participants were found to be sensitive to one weather factor, while about 12 percent were sensitive to two factors.
Study author Alan Rapoport, MD, director of the New England Center for Headache and a clinical professor of neurology at Columbia University College of Physicians and Surgeons in New York City suggests that people who think they might have weather-triggered migraines track their headaches. "Any good headache specialist should have a patient tracking their headache on a calendar," he says. "It's difficult for patients to do as careful a study as we did, but they can try to correlate the weather with the degree of headache they have." Those who determine that they are prone to headaches when the weather pattern is changing, for example, could carry their acute medications with them at that time, or take their preventative medication before the weather change to avoid a migraine.
It's not yet understood why weather cause migraines. "We know that migraineurs have an inflammation in the meninges, or the covering of the brain, as well as dilation of the blood vessels in the meninges," Dr. Rapoport says. "Exactly how weather patterns trigger the abnormalities that start the migraine process is not yet known." The next step, he says, is to figure out exactly how weather triggers a headache attack, so that these headaches can be more successfully prevented or treated.