One of the most widely accepted verities in the news business is that when temperatures go up, violent crimes are more likely to occur.
It seems logical, but is it really true?
The reasoning is simple:
People are living in crowded households and neighborhoods. City streets and buildings act like heat magnets, increasing the temperatures and stretching the heat into the evenings.
Buildings are packed together, reducing breezes. People get sweaty and sticky, which makes them uncomfortable and short-tempered.
The next thing you know, a guy says something, punches are thrown and, oh boy, here come the cops.
But there is also evidence against the heat/violence theory, and scientists are sharply divided on the subject.
When you look across the globe, you can find evidence both for and against.
Honduras is hot, and it also has the highest murder rate in the world, 91.6 homicides per 100,000 people. Canada, meanwhile, has the among the lowest rate, 1.6 per 100,000 residents.
But chilly Greenland's murder rate is 19 per 100,000 while in Oman it is less than 1 homicide per 100,000 people, even lower than Canada. The average year-round temperature in Oman is 83 degrees, while the average temperature in Greenland is below zero for seven months of the year.
If temperature is relevant, why is the murder rate in southern Africa 30.5 while in northern Africa, along the equator, it is only 5.9.
Maybe the variation has more to do with other sociological factors, like democracy. Some of the nations with the most repressive, top-down governments have the lowest crimes rates.
In the U.S., the heat/violence correlation seems stronger.
In 2012, Business Week declared Maine the most peaceful, least violent state in the U.S.
Yes, we are crazy safe here. We have the least number of violent crimes (per 100,000) in the U.S., the fewest number of police officers to population and the lowest percentage of people incarcerated.
Our homicide rate is a very Canadian-like 1.8 per 100,000 people.
Vermont and New Hampshire are second and third respectively.
Sweltering Louisiana, meanwhile, was rated the least safe with the most murders (11.2 per 100,000), the highest number of police per capita and the most people incarcerated of all the states.
Out of every 100,000 Louisiana residents , 543 of them live behind bars. In Maine, the same rate is 84.
Tennessee and Nevada were rated the second and third most dangerous states respectively
In 2009, the New York Times did an extensive study of homicides in New York City and around the nation.
Here's a tip: You are far less likely to become a homicide statistic if you are home watching TV or in bed between 10 p.m. and 6 a.m. Being out and about during those hours is far more risky.
The most homicides in New York actually occurred in Septembers, with an average of 52, but that wasn't much different than March, 48.
The Times pinpointed 10 p.m. on any warm Saturday night in September as the most deadly time to be in the city.
You probably could have guessed this, but women are far less likely to be either killers or victims. Of the 508 people killed in 2008 in NYC, only 17 percent were women, almost all murdered by someone they knew, like a boyfriend, husband or relative. Only 8 were killed by strangers.
But scientists have some other insights on the heat/violence link.
Several studies have found that violence does rise with temperature, but only to a point, which seems to be about 80 degrees, and then it gradually subsides as temperatures get warmer.
Researchers have a sociological explanation for this, the Routine Activities Theory, which means when people are out mixing with other people they are more likely to conflict.
When the temperature is uncomfortably cold they stay home. When it gets too hot, they slow down, seek shade or retreat to air conditioning.
In the summer, when daytime temperatures are higher, people may be at work or relaxing in the shade or at the beach.
But on summer nights, when temperatures fall back into the 80s, people are in their comfort zone and socializing with other people.
Add in some night-time activities, like drinking, dancing, bar hopping and nightclubbing, and the conflicts are more likely to turn violent.
Some scientists also point out that hot weather brings about physical changes like increased heart rate and blood circulation along with increased production of testosterone and adrenalin.
So, there probably is a connection between heat and violence, but it's not exactly what we thought, that the highest temperatures make us the most violent.
Instead, it's when we are the most comfortable and interacting that trouble is most likely to occur.
The opinions expressed in this column reflect the views of the ownership and the editorial board.