Basic characteristics of intentional homicide cases and climate parameters for the nine cities during the study period. City Study period No. of Mean Mean annual intentional homicide rate Daily mean climate parameters, mean + SD cases population (1/100,000) Tmean ('C) min-max Tmean RH (%) precipitation(mm) ('C) Chicago 2007-2017 5591 2,749,282 18.5 11.0 + 11.1 -23.9-33.2 63.3 + 12.2 3.1 + 8.3 Detroit 2009-2017 3016 703,918 47.6 10.4 + 10.7 -20.0-31.0 65.8 + 12.2 2.6 + 6.8 Fort Worth 2007-2017 397 781,117 4.6 19.3 + 9.1 -8.7-36.1 58.4 + 14.8 2.6 1 8.8 Kansas City 2009-2017 1846 470,308 43.6 13.3 + 10.9 -18.3-34.3 63.9 + 13.1 3.1 + 9.6 Los Angeles 2010-2017 3256 3,903,613 10.4 18.5 + 4.1 7.4-32.2 56.6 + 17.1 0.8 + 4.4 Louisville 2009-2017 461 605,528 8.5 14.5 + 10.1 -17.6-33.3 63.4 + 12.2 3.7 + 9.6 New York 2007-2017 4484 8,319,627 1.9 13.4 + 9.8 -13.4-33.6 58.0 + 14.1 3.5 + 9.3 Tucson 2009-2017 382 528,798 8.0 21.3 + 7.8 -2.8-37.1 30.7 + 15.6 0.7 + 3.1 Virginia Beach 2013-2017 90 450,057 4.0 16.5 + 9.0 -9.4-32.5 64.7 + 12.5 3.9 + 11.9 Total 2007-2017 19,523 18,512,248 10.6 15.2 + 10.2 -23.9-37.1 58.1 + 17.2 2.7 + 8.3 Note: SD = standard deviation; Tmean = daily mean temperature; RH = relative humidity; mean population represents the average population during the city- specific study years; the total mean annual intentional homicide rate was the weighted average (by population) of city-specific rates.