Suicide and homicide rates: their relationship to latitude and longitude and to the weather.

The variation of suicide and homicide rates in the major standard metropolitan statistical areas of the United States was explored to see whether regional variations in temperature and precipitation could account for some of the variation. Controls for temperature eliminated the North-South variation in suicide rates, but not the North-South variation in homicide rates or the East-West variation in suicide rates. Only the correlation between precipitation and homicide rates survived controls for latitude and longitude.