Disagreements that might cause minor annoyance on a cool day have a way of escalating when the mercury rises. Most riots that have occurred in the United States have happened when the temperature was between 75 and 89 F (23-31 C)--warm enough to increase tensions, but not hot enough to make people too lethargic to be bothered with fighting.
The unseasonably hot summer of 1967 set off a spate of racially-charged riots across the country including 164 incidents in such cities as Cleveland and Newark, but none would be as devastating in its long-term effects as the five day siege in Detroit which resulted in 43 deaths, 7,300 arrests, and property damage of $60 million.
