Many migraine sufferers have found that their pain can be triggered by changes in the weather, but previously there was little scientific evidence, though some studies suggested a possible link.

Now, an international team has carried out the study and found that changes in air pressure can increase the chance of developing a painful headache, the latest edition of the 'Neurology' journal reported.

Researchers, led by the Beth Israel Deaconess Medical Centre in Boston, have based their findings on an analysis of 7,054 patients who went to their hospital casualty department complaining of severe head pain over a period of seven years.

They found that a rise in temperature of five degrees Celsius from the previous day increased the chance of a severe headache within 24 hours by 7.5 per cent. There's also a more modest increase in the risk of suffering head pain within 72 hours if air pressure fell.

Experts have welcomed the research.

Prof Peter Goadsby of the Institute of Neurology in London said that the study was "interesting". "The challenge for clinical science is to link this seemingly odd trigger to the brain mechanisms involved in migraine," he was quoted by 'The Daily Telegraph' as saying.