A persistent area of high pressure over the region for much of July brought record heat to western South Dakota and northeastern Wyoming. High temperatures regularly reached the 90s, and several heat waves pushed readings well above 100 degrees.
July 15 was the hottest day of the month, when many locations tied or exceed their all-time record high temperatures. An official National Weather Service cooperative observer 8 miles west-northwest of Usta in southeastern Perkins County recorded a temperature of 120° F that day, which tied the all-time record high temperature for the state of South Dakota set July 5 1936 in Gann Valley.
Average temperatures for the month were also some of the warmest ever recorded. The Rapid City Regional Airport had the hottest July since observations began in 1942. It was the second hottest July ever at the East Rapid City National Weather Service Office, with only the infamously hot summer of 1936 warmer than this year, and the ninth driest July since records began in 1888.
Locations which set all-time record highs include:
Location New Record Previous Record
Cottonwood 2E 117 116 on 7/20/1910
Philip 116 113 on 8/26/1970
Milesville 5NE 116 115 on 7/24/1952
Interior 3NE 114 111 on 7/06/1973
(Badlands National Park)
Rapid City Airport 111 110 on 7/08/1989
Pine Ridge 111 108 on 7/25/2003
Spearfish 109 (twice) 106 on 7/09/1954
Fort Meade/Sturgis 108 (twice) 107 on 7/16/2005
Pactola Reservoir 101 100 on 7/09/1989
Mount Rushmore 100 (tied) 100 on 7/11/1985