Public Health Crime
Heat  ImagesbyK/iStock.com

Summer in the city.

September 25, 2017

Philly's lingering summer weather could mean higher crime rates, research suggests

Though we’re entering the final week of September in what is officially autumn, it still feels like the throes of summer outside. While some may be reveling in this lingering warm weather as others long to don packed-away boots and sweaters, it could also mean lingering high crime rates.

Drexel University researchers looked at a decade of crime in Philadelphia, from 2006 to 2015, and found that, regardless of the season, violent crimes and disorderly conduct were far more common during times of higher daily temperatures.

Accordingly, the hottest days between May and September had the highest crime rates of that period. During those months, violent crime rates were 9 percent higher when temps reached 98 degrees.

The rest of the year, from October to April, warmer days still led to more crime, though the spike in crime rates during warmer days was far more dramatic. Researchers concluded a 16 percent increase when the weather reached 70 degrees in the years' colder months.

“Our findings are reasonable when you think about social behavior,” said Leah Schinasi, an assistant professor at Drexel who conducted research for the study.

“When temperatures are extremely cold or hot, people stay indoors. But as temperatures become more comfortable, more people are outdoors, which presents greater opportunity for crime."

Schinasi said more neighborhood-specific research that delves into infrastructure and area traits would help in identifying crime variables more clearly.

Nonetheless, the uptick in crime during warm-weather days is particularly concerning as climate change continues to shift the weather patterns we’re used to.

“It is important to recognize the implications of these climate change effects for public health, including changes in crime rates,” Schinasi said.

“Although these results back up police officers’ anecdotal reports about the relationship between temperature and crime, it’s nice to have data to confirm these reports. Our results might help inform local law enforcement about ways to allocate resources during different seasons and with consideration of the local climate.”

The full research was published in the Journal of Urban Health.