Winter reduces criminal activity, researchers find

« I don’t know why it’s an urban myth because it’s so well-documented … When the weather’s cold, there’s quite a bit less crime.»


The worse the winter, the safer the streets — or so goes the urban legend.

Compared to last winter, average temperatures are about the same, but there has been three times more snow.

Coincidentally — or maybe not — crime is down 12 per cent.

"Weather does seem to play a role (but) we can’t specifically attribute the drop to the weather," said Toronto police Const. Wendy Drummond. Or can we?

A joint study by professors at Harvard, Berkeley and Brigham Young universities proves the myth is actually fact.

"I don’t know why it’s an urban myth because it’s so well-documented," said Lars Lefgren, an associate economics professor at Brigham Young in Utah. "It sort of stands out like a sore thumb: When the weather’s cold, there’s quite a bit less crime."

The study, which was published last year in the Journal of Human Resources, shows when the average temperature dropped by 10 per cent in a week, crime in general fell by 5 per cent. The opposite is true when the mercury rises.

More interesting, at least in Toronto’s case, are the statistics relating to precipitation. Data show that for every inch (2.5 cm) of precipitation per week, there’s a 10 per cent reduction in crime that week.

Using the FBI’s National Incident-Based Reporting System, researchers analyzed crime in 116 U.S. jurisdictions for 1995-2001. The database tracks violent crime and property crime — which includes robbery, car theft and shoplifting — but not drug-related crime.

"We looked at hundreds of U.S. cities and matched those crimes to the local weather conditions in the county," said Enrico Moretti, an economics professor at Berkeley in California.

"We found both violent and property crime tend to be higher when it’s very hot and they tend to decline when it rains or snows."

The study also examined crime statistics after a heat wave or cold spell to answer the question: If you prevent someone from committing a criminal act today, to what extent will they commit that act later?

Statistics showed a spike in criminal activity after chilly or snowy weather and a dip in crime following warm weather.

safer streets

  • University of Berkeley professor Enrico Moretti said Toronto’s decline in crime is likely attributable to precipitation rather than temperature. Nearly 130 cm of snow has been dumped on the city since January, compared to 46.4 cm of snow in 2007.