What have scientists concluded through studies over the years? [originaltext]

Scientists have interrogated the link between seasonal weather and crime, consistently finding that warm summer temperatures yield more violence. Higher heat tends to fray nerves and shorten tempers, inspiring aggression, which is why riots tend to happen in the warmer months.
        Scientists in Colorado, however, recently explored what happens to crime when winters become warmer, which is the first attempt in this regard. Their study found that milder winters — which are occurring more frequently as a result of climate change — caused regional crime rates to rise over the past several decades. The researchers think crime increases during a warmer-than-normal winter because people don’t hunker down inside to stay warm.
        "Basically, more pleasant weather increases the chance that people will go out to restaurants, cafes, parks, whatever it may be," Ryan Harp, a doctoral candidate in the University of Colorado Boulder’s department of atmospheric and oceanic sciences, and the study’s lead author said, "and a potential perpetrator and potential victim will cross paths without a guardian present." By "guardian" he means someone in a position to prevent or stop a crime, such as a police officer.
        Harp stressed, however, that the paper, which appears in the journal GeoHealth, doesn’t look directly at the influences of climate change, but simply how crime totals for each month varied with the temperature for that same month.
        "Though it’s easy to make a connection between our study and climate change — in fact, taking a look at that is one of our next projects — we only looked at how the year-to-year swings in temperature connected with the year-to-year swings in crime for a particular location," Harp said. "Both temperature and violent crime go up and down each year, but all that we were interested in was whether or not they do so together."
        The answer appears to be yes, although it skirts the notion that hot temperatures drive aggressive behavior. Rather, it suggests that weather changes peoples’ daily activities, spurring more crime. Scientists say three factors lead to crime during a mild winter: a motivated offender, a suitable target and no one there to stop it.