For years, community activists and police wondered if temperatures and weather have an effect on crime. Recently, new studies have shown a direct relationship between the temperature outside and the crime rate.

Cold Temperatures and a Drop in Crime


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Matthew Ranson, an economist for consulting firm Abt Associates, put together a study that reviews the relationship between crime and temperature using 30 years of data from across the country. Using nine major crime categories, Ranson found that offense rates drop when the temperature goes below 50 degrees Fahrenheit. Additionally, many crimes continue to decrease as the temperatures get colder.

Crime reports during the cold snap in January 2015 seem to support that. New York City went 12 consecutive days without a murder, which was the longest murder-free stretch since the police department began collecting data in 1994. Additionally, major crimes were down 34 percent in Boston.

One Crime That Doesn't Drop With Temperatures

While most crime rates seem to drop as the temperatures plummet, there is one exception: car theft. In fact, car theft incidences actually jump when temperatures drop below 10 degrees Fahrenheit. This increase in crime is likely because car owners leave their vehicles running with the heat on to warm up their cars or defrost their windows. An unattended car that's running is the perfect opportunity for a car thief.

Changing Opinions on Crime

In 1935, J. Edgar Hoover, the man responsible for the FBI, believed that crimes such as burglary and robbery were more frequent in the winter than during the summer. However, the Department of Justice reports that burglaries are 10.5 percent more likely in the summer than in the winter. Unfortunately, it's not just burglary that peaks during the summer months — violent crimes are also significantly higher.

Warm Temperatures and an Increase in Crime

While it seems like warm temperatures bring out the worst in people, it's actually our changing habits that bring about an increase in crime. During the summer, many people start to leave their windows open to try to cool off their houses. Additionally, they tend to leave the house more frequently as they attend different summer activities. Both of these activities give burglars a perfect opportunity to enter the home.

Additionally, even though The Wall Street Journal found that July was the deadliest month in terms of homicides in New York City between 2002 and 2009, it's not necessarily because warmer temperatures bring out more aggression leading to more assaults. As James Alan Fox, a professor of criminology at Northeastern University points out, it's more likely that there are more people out and about, which means there are more potential victims outside.

While crime seems to spike when it's warm outside, if temperatures rise above 90 degrees Fahrenheit, crime starts to decline again. People seek shelter inside and no longer spend as much time outside.

In the end, while the weather may have some influence on crime, it doesn't cause or prevent it. As such, it's still important to take basic safety precautions throughout the year, no matter what the weather is like outside.