Everyone knows that heavy rain makes car accidents more likely. But a recent study by the American Meteorological Society found that even drizzle can be deadly, increasing the risk of a fatal crash by 27 percent.

Researchers from the North Carolina Institute for Climate Studies analyzed 125,012 fatal crashes in the Lower 48 states from 2006 to 2011, using radar data to identify how hard rain, snow or ice was falling when the accidents occurred.

Even rain of less than one-tenth of an inch per hour raised the risk of a fatal car accident, according to the findings.