A number of studies have explored the effects of weather on headaches, but with mixed results. This study was designed to tackle the headache-weather relationship once again, adding in perceived influence of weather on headaches.

What the researchers wanted to know: How much do headache sufferers believe weather influences their headaches, and what are the actual effects of weather on headache?

What they did: Researchers recruited 77 migraine sufferers from a headache clinic in Stamford, Conn., and asked them to keep a headache diary for two to 24 months. All the patients had to do was give a rating, three times a day, of how severe their headache was at that moment (if they had one at all). Then, since they wanted to look at both the subjective and objective effects of weather, the researchers broke up the rest of the study into two phases. In Phase 1, patients filled out a questionnaire about their beliefs regarding the influence of weather on their headaches. In Phase 2, researchers got detailed information from the National Weather Service on weather near patients' homes throughout the same time period that the headache diaries were kept. Using these data, researchers studied the impact of three distinct factors: temperature in combination with humidity; weather changes; and barometric pressure.

What they found: Weather was often involved in headaches, but subjects gave it a little too much credit. While 62 percent believed their migraines were related to weather, only 51 percent actually demonstrated sensitivity to weather factors. And of those patients who correctly attributed their headaches to weather, most picked a trigger other than that found in the weather data. While patients were likely to blame low pressure and high humidity or rain, the most common (objective) trigger was temperature mixed with humidity: High humidity plus either high or low temperature was the biggest menace. Significant changes in weather came in second; barometric pressure, third. However, many patients' headaches appeared to be sparked by more than one of the three weather triggers.

What this study means to you: Although weather seems to be associated with headache, the average person isn't very good at telling which aspect of weather is the culprit. So, headache sufferers, don't pack your bags for another climate just yet.

Caveats: By restricting the study to only three factors, researchers left out other possible triggers that could have just as great an effect on headache. Also, this was a relatively small study.

Find out more: Links to migraine information from the National Library of Medicine: http://www.nlm.nih.gov

Read the article: Prince, P.B., et al. "The Effect of Weather on Headache." Headache. April 2004, Vol. 44, pp. 596–602.

Abstract online: http://www.ncbi.nlm.nih.gov