Contrary to the film noir myth, it turns out violent crime actually drops when it rains.

A new paper looked at every crime reported in New York City over 14 years, 2006-2020, matching each to the reported weather conditions at the time.

“Our results show that neither weather nor pollutants have a contemporaneous effect of on homicide,” the researchers – oddly based at the University of Otago, in New Zealand – said.

That’s likely because – and who couldn’t see this coming? – people are more likely to stay home when it rains.

But there was one substance that appeared to increase the likelihood of violent crime – and it comes from old-school combustion engine cars. 

“Higher concentrations of carbon monoxide increase violent crimes in a U-shaped relation,” said author Dennis Wesselbaum, a macroeconomist with an interest in climate change. 

Crime rates in New York fell markedly from the 1990s onwards, with one explanation being the removal of lead from gasoline. The paper was published this week in the Journal of Forensic and Legal Medicine.