We analyzed the relationship between the incidence of spontaneous intracerebral hemorrhage (ICH) and various meteorological data (daily atmospheric air pressure, air temperature, precipitation, humidity, presence of typhoons, occurrence of the rainy season, wind velocity, and wind direction) for patients at Teraoka Memorial Hospital in Shin-ichi Town, Japan, from January 1, 2001 to December 31, 2003. All data were analyzed by contingency table analysis and multivariate regression analysis. From January 1, 2002 to December 31, 2003, we identified high-risk ICH days as those days for which the preceding 3 days mean recorded air pressure of 1,015 hPa or more and then conducted a statistical comparison of the incidence of ICH on high-risk ICH days with that on the other days. Our subjects were 164 patients with ICH. The relative risk of high-risk ICH days is 1.46 (Fisher's exact test, p=0.04). Mann-Whitney's U-tests indicate ICH tends to occur on days with lower maximum air temperature. Multivariate logistic regression analysis revealed that 3 incidences influence the occurrence of intracerebral hemorrhage (p<0.01 each): (1) days associated with 4-day periods of mean air pressure in excess of 1,015 hPa; (2) days during which a typhoon was approaching; and (3) days with west or southwest wind . Detailed examination of meteorological data indicates a relationship with the incident rate of ICH.