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Last Monday a man wearing a bandana and wielding a shotgun walked down a narrow street in Kensington and sprayed buckshot, wounding seven people, including a little girl, and leaving two men in critical condition. Just days before that in West Philadelphia, in a separate act of widespread violence involving a shotgun, 10 people at a block party were wounded.

Could these acts of violence be signaling Philly is in for a violent few months? It’s summertime; it’s generally accepted that when warm weather hits in major cities, neighborhoods erupt as more people are outside and unsupervised youth are out of school.

Now, Philadelphia has made great strides over the past several years in decreasing rates of violence — even more so than the national average. Since Mayor Michael Nutter took office in 2008, the homicide rate decreased from 391 the year before he took office down to less than 250 for each of the last two years. The rate is now at a historic low, and is on track to be so again this year.

But there’s an old idea that when temperatures rise, so do the rates of violent crime. In recent years in Philly, though, the data simply isn’t consistent with this when it comes to homicide and shooting victims. Instances of smaller crimes that are much more common than murder, though, provide a glimpse into what could be occurring when it gets warm from June to September.

Each summer, police across the country review their strategies for how they can better monitor the streets. It’s a must, especially with kids out of and around the neighborhoods. But is that a contributing factor to recent shootings in Kensington and West Philly? Or are they anomalies — headline-grabbers that don’t represent the norm?

“It might look like no one knows what’s going on in West Philly,” said Caterina Roman, an associate professor of criminal justice at Temple. “But behind the scenes, [police] have theories and are working to identify people and how to put together the best criminal case. Philly has its stuff together when it comes to gathering information.”

Here’s a breakdown of the violence in Philly and what it means as we head into the hottest days of the year:

Homicide and shootings

When it comes to gun violence, data shows a weak correlation between the summer months and the incidents that actually occur. Here’s a look at the number of homicides that occurred each month from 2009 to 2013:

The same can be said for just shooting incidents that aren’t considered homicides. There seems to be some increase in incidents during summer months, but nothing quite as dramatic as what might be expected when you hear that violence rises as temperature does. Here’s a look at a month-by-month breakdown of shooting victims in Philadelphia over the last several years:

When at looked at month-to-month, the correlation isn’t exceptionally strong. But this graph, created using Open Data, looks at just homicides since 2006 and overlays the number of homicides that happened on each day that was a specific temperature. The number of incidents peaked in the low to mid-70s. After it got warmer than 80, incidents dropped significantly.

Philadelphia Criminal Homicides by Temperature, 2006-2015(May)

Philadelphia Police couldn’t say if they sense more violence in the summertime this year when more people are out and about. But at the end of the day, while homicide and shootings will most often lead the evening news, they’re not always the best indicator of crime trends.

Other crime

Police keep detailed statistics about the number of violent crimes and property crimes (both considered Part 1 crimes) that take place each week of the year. Let’s look at 2014 as an example. Violent crimes include homicide, rape, robbery and aggravated assault. Property crimes include burglary, theft of a motor vehicle tag, theft from a person, theft from an automobile, theft, retail theft and automobile theft.

Broken down by week, here’s a look at what last year’s non-homicide, but still serious, crimes looked like:

See the difference? In this case, there’s a much clearer correlation between what week it is (weeks 20 to 40 can generally be associated with higher temperatures) and the amount of serious property crimes that are taking place. These trends are consistent with what’s seen in major cities across the country.

So why does this happen?

There are number of theories out there that explain this phenomenon; some of them are competing theories. Roman, who spent nearly 20 years at the Urban Institute in Washington, D.C., said it’s not necessarily temperature itself that causes a rise in crime rates throughout cities, but it’s the opportunities that those months pose for young people, specifically young men. But she offered these theories as to why the increases often occur:

  • Opportunity. More people are outside, and the rates of violent crime flattens out above 85 degrees, because more people go indoors when it’s sweltering hot. Additionally, more people leave town in the summertime and their homes and cars are more inviting to motivated burglars.
  • A few studies have actually correlated heat and aggressive behavior and have found a link there. But cities overall can’t definitively say this, because there’s no one out there measuring body temperature on a random sample of people in various cities. Roman says with Philly’s stats, it’s hard to but two and two together.
  • The routine activities theory, which just says that in the summer, there are more people out and about — and therefore more of a chance for crime.

But one of the biggest changes in the summertime months, Roman says, is young kids and gang violence. Many don’t have summer jobs and are hanging out with neighborhood crews. The sizes of these crews increases when high school-aged kids gets involved, she says, and when the groups have beef with each other, things can turn violent quickly.

“When someone says ‘a gang,’ people think that these kids are perusing the streets looking for trouble,” she said. “But mostly these are kids who look like normal kids. They don’t have colors or things like that, but they hang around and they’re affiliated and will protect their territory. And that’s an MO.”

What police can (and do) do

Whether they know it or not, police keep close track of these neighborhood groups. Even if they don’t have a widely-known name, police will assign them one and keep tabs on certain members that seem ready to beef with other crews. From there, they’ll work to find a way to diffuse the situation before violence occurs.

These techniques are common across America, especially in large cities — Philadelphia is among the most violent of the largest cities in America. Roman said police collect large amounts of data on youth groups that are especially active, trying to figure out which ones “are hot” and which ones are heading toward “a flare up.” Analysts can synthesize the data, and from there detectives can stop a person on the street, especially if there are priors and they know the person is carrying.

Other work has been done in Philadelphia to drastically decrease violent crime over the last several years. Police assigned to schools during the year are often re-assigned to keep tabs on students during the summer. School diversion programs can be most helpful in these months, because they get problem kids services instead of expelling them to the streets. Different deterrence programs have been implemented in different neighborhoods that are aiming for long-term changes.

Roman highlighted two other trends in policing that could be on the bubble that could decrease violence in the summer, but that Philadelphia Police haven’t implemented in a widespread way yet:

  • In Chicago, analysts have data to identify problem kids and, from there, predict which youth are next to be targeted or next to become offenders. This is where the school diversionary program can come in, because those kids identified by police can be offered services.
  • Police already work closely with hospitals, but some are considering having hospitals implement a response program where kids and families involved in violent crime who come to the hospital will be given information about what do and how to link up with community outreach organizers.

But maybe the best way Roman says the city can divert violent crime over the summer? Keep the libraries and pools open, even if the budget gets tight.

“You can’t close the pools in a city like ours with neighborhood issues,” she said. “Just having well-staffed, positive, pro-social opportunities for kids will go a long way.”

Photo: Fox29

Anna Orso was a reporter/curator at Billy Penn from 2014 to 2017.