There is no scientific evidence that hot weather causes crime, but experts have found strong correlations between rising temperatures and more frequent violent crime. To keep the public safe, officers must be aware of this relationship and anticipate how resource availability and workload may change in the future.
With higher temperatures come higher crime rates
Prior research showed that when temperatures are higher, people are more likely to engage in unlawful activities. Craig Anderson, a professor at the University of Iowa, published a report in 2001 that assessed crime rates during the summer months in the U.S., finding a 2.6 percent increase in assaults and murders above the statistics for winter months.
Anderson explained that higher temperatures may lead to discomfort, causing people to act out in more violent ways. This effect is especially pronounced when people spend more time outdoors—something that most of us do during summer months—often sharing public spaces with others.
In another study examining the behaviors of Chicago residents during the summer, researchers found a surge in violent crime on Saturdays, Sundays and Mondays, days when people share public spaces most. Under these circumstances, others’ personal possessions may become more accessible to thieves, and tensions among community members may escalate more easily.
Laura Brinkman, a former associate director at the University of Chicago Crime Lab, noted that increased crime in the city came during schoolchildren’s summer break: “Juveniles are the most likely to commit crime, in general, so it seems almost obvious that crime may peak during summer months when students are off from school with idle hands.”
Studying data from the last thirty years, economist Matthew Ranson leveraged the connection between temperature and crime to project future impact on police departments due to rising average temperatures around the globe. Ranson calculated that by 2099, law enforcement agencies would face an additional 22,000 murders, 1.2 million aggravated assaults, 2.3 million simple assaults, 180,000 rapes, 2.2 million cases of larceny, 1.3 million burglaries and 280,000 vehicle thefts—all attributed to climate change. The costs of fighting these additional crimes would range anywhere from $38 billion to $115 billion.
Anticipate weather-related changes to policing
Not all researchers agree with Ranson’s extrapolation. His presumption of a linear relationship between temperature and crime, where extreme heat leads to ever-increasing violence, is countered by studies that suggest temperatures reach thresholds where the relationship breaks.
A study analyzing crime rates in Dallas between 1993 and 1999 discovered that rate of increase in violent offenses lessened after temperatures reached 80 degrees Fahrenheit. Furthermore, at 90 degrees the relationship between temperature and crime became negatively correlated, or curvilinear. Eventually, the increasing heat becomes so oppressive, it pushes people back inside for shade and air-conditioning.
Linear and curvilinear interpretations of crime and temperature paint two distinct pictures of future criminal landscapes. Whereas Ranson may see all law enforcement resources similarly taxed as the temperature rises, the existence of criminal thresholds means a shift in resource needs, with violent crime moving north and law enforcement expertise likely migrating with it. Cities in the South, typically home to more violent crime than their cooler counterparts, may see relief in the future when summer temperatures become unbearable.
Changes in climate—such as weather volatility, rising temperatures, and natural disasters—may help push people to act irrationally. Questionable behavior by citizens impacts the workload of emergency responders. Understanding past crime-temperature relationships—and tracking how each community is adapting to new weather patterns—will inform future law enforcement strategy. This knowledge may not help officers prevent crime altogether, but it will place them in a better position to anticipate future emergencies.
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