Last year the Daily Telegraph pointed out that: “Hot weather prompted a rise in police calls”  and conventional wisdom holds that violent crime increases during hot weather. Even our language is peppered with references to “hotheads”, whose anger “simmers” until they either “lose their cool” and “blow up” or finally “cool down”.

Florida State University researchers found that, over two years, violent assaults consistently increased in Minneapolis as temperatures rose toward the 80s. They attributed the change partly to “social opportunity”: when the temperature goes up, more people spend more time outside. (In other words, they argued that weather affects crime rates more by driving them outdoors where they are more likely to encounter each other or an unsecured house door rather than by making people more susceptible to violence.)

Craig Anderson, from Iowa State University, argued there is a linear relationship between heat and violence, with assault rates peaking at the highest temperatures his model to explain heat-induced aggression is illustrated here . He argues that a straight-line relationship supports various psychological and physiological processes. In hot weather, the body exhibits changes — increased heart rate, blood circulation and sweating, and metabolicalterations— associated with sympathetic nervous system activity, which in turn are linked to fight-or-flight responses. Hot weather also increases testosterone production, tilting that equation towards fight.

Anderson warns that physiological explanations are not proven, but he thinks there’s evidence that heat fuels anger through a variety of psychological effects. (Though as Wired.com points out, the rationale might not be so simple: “Studies show that in hot weather people are more likely to interpret neutral signals as signs of hostility, and less likely to condemn violence.”)

In fact this relationship is not a linear one – crime drops at very high temperatures. James Alan Fox, Professor of Criminology at Northeastern University, suggests there’s an upper limit to any correlation. “Crime levels are highest when the temperature reaches the mid-80s; but especially uncomfortable conditions with the mercury over 90 degrees result in less violent crime. Temperature has some effect on violence in the home, but a much stronger impact on violence in outdoor or commercial settings. In both situations, however, the rate of violence tends to decline when temperatures reach the 90s.”

The correlation between heat and violent crime shown in @jamesalanfox ‘s article is stark. Perhaps the long range weather forecast may be more effective indicator of potential workload and the need to change staffing levels than you may have thought…

Reposted with permission from an original article by crestadvisory.com – (Additions and any mistakes are mine!)

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