TO DEVELOP EMPIRICAL EVIDENCE FOR THE INFORMAL OBSERVATIONS WHICH ASSOCIATED THE RIOTS OF THE 1960'S WITH THE UNCOMFORTABLE HEAT OF URBAN AREAS IN THE SUMMER, SEVERAL RESEARCH PROJECTS EXAMINED THE WEATHER CONDITIONS AND THE CRIME RATES OF THE 1960'S. SYSTEMATIC OBSERVATIONS REVEALED THAT A LARGE PROPORTION OF THE SERIOUS INCIDENTS OF COLLECTIVE VIOLENCE OCCURRING IN MAJOR AMERICAN CITIES DURING THE LATE 1960'S DID TAKE PLACE DURING THE HOT SUMMER MONTHS, WHEN HEAT-WAVE OR NEAR HEAT-WAVE CONDITIONS PREVAILED. THESE INITIAL FINDINGS DO NOT PROVIDE ANY DIRECT INFORMATION CONCERNING THE NATURE OF THE RELATIONSHIP BETWEEN WEATHER AND AGGRESSION. HOWEVER, AN EXAMINATION OF ARCHIVAL DATA PERTAINING TO 102 INSTANCES OF SERIOUS CIVIL DISORDER DURING THE PERIOD OF 1967 TO 1971 DOES INDICATE THAT THE FREQUENCY OF COLLECTIVE VIOLENCE AND AMBIENT TEMPERATURE WERE CURVILINEARLY RELATED WITH THE FREQUENCY OF SUCH EVENTS INCREASING WITH TEMPERATURE THROUGH THE MID-80'S, BUT THEN DECREASING SHARPLY WITH FURTHER INCREMENTS IN TEMPERATURE BEYOND THIS LEVEL. ADDITIONAL FINDINGS INDICATE THAT AMBIENT TEMPERATURE INCREASED SIGNIFICANTLY DURING THE 7 DAYS PRECEDING THE OUTBREAK OF VIOLENCE, REMAINED STABLE DURING ITS OCCURRENCE, BUT THEN DECREASED IN THE 3 DAYS FOLLOWING ITS TERMINATION. FURTHER RESEARCH SHOULD CONSIDER THE EFFECTS OF HEAT-RELATED FACTORS SUCH AS ALCOHOL CONSUMPTION AND OVERCROWDING. TABULAR DATA AND REFERENCES ARE PROVIDED. (TWK)