[Does weather modify headaches? An empirical evaluation of bio-weather categorization]

Headache patients frequently refer to the weather as a triggering factor for their headaches. Apart from a literature review, we tested empirically the generally used classification of weather epochs into a so called bio-weather categorization.

Headache diary data (frequency, duration, intensity) of 98 patients in a headache trial were correlated with the concurrent bio-weather classification.

Correlations were small and significant only for the summer-half of the year (contingency coefficients between 0.04 and 0.06). The classification of certain types of weather as headache prone as used in the current bio-weather classification could only partly be verified.

There is a clear but small correlation between headache and weather. More, and more fine-grained, studies are warranted, especially for identifying those patients at risk for weather prone headaches. Clinically more important is the weather as a source of causal attributions.