People who complain of feeling under the weather may be speaking literally, as two studies illustrate. Migraine sufferers often complain that weather triggers their intense headaches. In Alberta, Canada, those complaints revolve around chinooks, the warm winds that sweep the area during winter. So Werner Becker, M.D., a neurologist at Alberta's Foothills Medical Center, tracked weather reports for two 10-month periods and asked 75 migraine sufferers to record, in a diary, the days that they experienced headaches. In fact, incidence of migraines was higher on days when chinooks were blowing and on the days beforehand. While Becker isn't sure how the winds might cause migraines—it could stem from a drop in barometric pressure, he notes in the journal Neurology—the finding is good news for the migraine sufferers of Alberta, who can now predict headache onset by watching local weather reports.

Another study, published in the Journal of Abnormal Psychology, suggests that excessively cold or hot weather may play a role in the development of schizophrenia. Study author Dennis Kinney, Ph.D., tracked the birth months of 78 schizophrenics—birth season has long been associated with schizophrenia, but not specific weather patterns—and discovered that schizophrenics whose illness was environmentally induced were twice as likely as those whose illness was inherited to have been born during a month of extremely hot or cold temperature, such as August or February. (Unlike people who develop the disorder early on, schizophrenics who inherit their illness have an observable eye tracking disorder.) Extreme environmental conditions may damage newborns' fragile nervous systems, believes Kinney, director of the genetics laboratory at McLean Hospital in Massachusetts. Learning more about how this works, he says, may help prevent certain forms of the disease.