The Rapid City Regional Airport recorded a high temperature of 100 degrees on Monday, July 18, the first day the temperature has reached 100 degrees since August 27, 2010. It is the first 100 degree day in July since 2007. The reading didn't set a record for the day, which remains at 106 degrees in 2006.
Humidity levels over far western South Dakota were also higher than normal, with dewpoints from 60 to 70 degrees. They contributed to heat index readings of 100 to 103 degrees, which were lower than heat index values over eastern South Dakota.
The downtown Rapid City National Weather Service had a high temperature of 99 degrees.