As temperatures climbed relentlessly this summer, homicides in Washington, D.C., fell just as dramatically, something an expert tells the Washington Examiner may not be a coincidence. Since Memorial Day weekend, the number of killings in D.C. has dropped by 44 percent compared to 2010. Before the holiday, homicides in D.C. were up 16 percent. “People say,’it’s too hot to kill, or I don’t have the energy to kill,” said Ellen Cohn, a professor at Florida International University studies connections between weather and crime. “It becomes more important to find a drink than exact revenge.” Criminologists have long noted that crime can rise in the summer months. People become more aggressive and lash out. Rapes, riots, and 911 calls go up. Part of that is that male teens are out of school and unsupervised, the days are longer, and outdoor activities increase.
Yet searing heat may drive people indoors, and even dull the ardor to keep cycles of revenge killings going. “Violent crime rises with temperature — but only up to a certain point,” Cohn said. Once it gets too hot, the violence can drop off, she said. “It’s like the fight-or-flight theory, when it becomes too hot, criminals flee to places cooler.” Noting that Washington area weather has reached extreme levels, she added, “It may have reached the point that it’s so blasted hot outside that violent offenders, like everybody else, are staying inside.” D.C. Police Chief Cathy Lanier doesn’t buy that theory. She said the credit belongs to the Metropolitan Police Department’s focus on preventing violent crime. “This is a sign of our success,” she said.