The files of all patients admitted to the Geneva and Lausanne University Eye Hospitals during 1972, 1973, and 1974 with the diagnosis of acute glaucoma were examined. Only those cases in which the exact date of onset and recorded, and in which the diagnosis of acute closed-angle glaucoma left no doubt, were retained. The dates corresponding to the first symptoms in the 34 remaining cases were submitted to meteorlogical and statistical study. Twenty of these cases (60%) occurred during the same meteorological condition: an advection of cold maritime air from the north-west at the rear side of a low-pressure system together with, or following, the passage of an active atmospheric disturbance. These conditions occurred only 57 times during the period of 1,096 days under study.