Excessive Heat in Sully, South Dakota

The region witnessed three days of high heat and humidity in late July. Peak temperatures for the three day period included a high of 105 degrees measured at the South Dakota extension mesonet station 7 miles southwest of Hayes, 104 degrees at Pierre municipal airport and 103 degrees at the department of transportation weather station in Hayes. The South Dakota extension mesonet station 7 miles southwest of Hayes also observed a high temperature in excess of 100 degrees for all 3 days.

In addition to the heat, high humidity with dewpoints in the low to mid 70s resulted in widespread heat index values at or above 100 degrees. A public weather station in Pierre observed a heat index of 108 degrees on July 27th, with Pierre municipal airport measuring a peak heat index of 107 degrees on July 25th. 29 weather stations recorded a peak heat index of 100 degrees or higher on July 25th, 18 on the 26th and a total of 25 stations observed a heat index of 100 degrees or more on the 27th.