• A new study shows that violent crimes increased by 50% on hot days compared to very cold days in Tshwane.
  • Violent and sexual crimes decreased on high-rainfall days, the study by the University of Pretoria shows.
  • The research looked at more than 1.36 million crimes reported during a five-year period.


A new study shows a strong link between hot days and violent crime.

Research findings by professor Gregory Breetzke from the department of geography, geoinformatics and meteorology at the University of Pretoria show a strong association between crime and climate in Tshwane.

The study looked at more than 1.36 million crimes reported over a period of five years. 

The findings, published in The Conversation, show that as temperatures climb, so too does crime, says Breetzke

Violent crimes increased by 50% on hot days compared to very cold days. Sexual crimes increased by 41% and property crime by 12%.

The study also looked at the impact of rainfall on crime, and found that violent and sexual crimes in Tshwane decreased on high-rainfall days.

Surprisingly, property crime was found to increase slightly on heavy rainfall days, though only by 2%.

The results could help the police better understand how weather affects crime patterns in South Africa’s urban areas and develop and implement appropriate crime prevention measures, says Breetzke.

The link between criminal activity and climate is nothing new, he adds. Over a century ago, Belgian scholar Adolphe Quételet observed that crimes against people reach a maximum during the warmer summer months, while crimes against property reached a peak during winter.

He later developed the temperature-aggression theory, which provides a psychological explanation for the increase in crime during warmer months. It suggests that warmer temperatures will lead to an increase in an individual’s frustration and discomfort levels and so increase the likelihood of aggression.

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