Quartz Africa recently conducted an experiment seeking to find out how weather and crime relate to one another in South Africa.

The results determine that there is a strong relationship; as temperatures soar, so do crime rates.

With this information, law enforcement can able to develop more comprehensive measures on preventing crime.

A Belgian sociologist, Adolphe Quételet came up with the temperature-aggression theory over a century ago. It hypothesizes that warmer temperatures lead to more discomfort levels in an individual, which raises a likelihood of aggression.

Quételet established this conclusion after observing that aggressive crimes such as assaults peak in the summer. Conversely, winter months see an increase in crimes against property such as home invasion and robbery.

The Research

First, the researchers obtained Tshwane’s climate data for 5 years from September 2001 to the end of August 2006 from the South African Weather Service.

Then, the team pinpointed the ten hottest days for each year. Again, that process was duplicated for low-temperature days, high-rainfall days, no precipitative days and random-rainfall days.

Next, the South African Police Services’ Crime and Information Analysis Center provided information on crime data for the same five year period. Location of each crime, date and time, and the crime committed were all obtained. In totality, 1,361,220 reported crimes across 32 different crimes (violent, sexual or property) were found within the five years.

Finally, a spatial point pattern test was used to determine if spatial patterning of crime is dependant on the weather.


According to the research, violent crimes saw an increase of 50 percent on warm days; sexual crimes rose by 41 percent and 12 percent for property crimes.

High-rainfall days prove to have the least amount of criminal acts. Violent and sexual crimes decreased on rainy days overall. In spite of this, property crimes increase by a small margin of 2 percent during heavy rainfalls.

The study concludes that temperature significantly influences violent, sexual and property crimes within South Africa. However, precipitation has little effect on illegal activity.

While this study determines that meteorological patterns do affect crime patterns, the issue of crime and violence is a complex issue that has many other factors, weather being only one of them.

More crime patterns can be analyzed with research like this and it can give police and citizens more of an insight on understanding criminality.

Featured Image via Wikimedia Commons.