What can cause migraines? The answer may vary depending on the individual. When the temperature climbs, so does the likelihood of developing a migraine or other severe headache. In one recent study, researchers found a 7.5% increase in headache risk for every 9 degrees Fahrenheit. Low barometric pressure, which often precedes rain, was linked to a small bump in non-migraine headaches. Strong smells — even nice ones — trigger migraines in many people. Why this happens is unclear, but the...