Forty-four adult patients suffering from either classical or common migraine recorded the dates of their attacks over periods of six months. Barometric pressure on the day of attacks, changes in pressure before attacks, days of the week and months of the year were correlated to the frequency of migraine attacks. The frequency of migraine attacks was significantly less when barometric pressure at 06.00 hrs was less than 1005 mb compared with pressures between 1016–1025 mb. A rise in barometric pressures of more than 15 mb over the preceding 24 hours was also associated with a significantly reduced migraine frequency. Attacks of migraine were more common on Fridays and Saturdays and during Autumn.