Excessive Heat — Day, South Dakota

2025-06-20 to 2025-06-22 · Day, South Dakota

Wider weather episode

High heat and humidity settled into the region between June 20th and 22nd. A high temperature of 106 degrees was observed by a mesonet station 2 miles south southwest of Fort Pierre, with 105 degrees observed by the COOP in the town of Kennebec on June 20th. 22 additional weather stations, mainly across central South Dakota, would top out at or just above the century mark. Thanks to dewpoints well into the 60s and low 70s, heat index values at or above 100 were quite widespread, with a mesonet station in Mellette topping out at 117, while Onaka, Stockholm and Straford would record peak heat index value of 115 degrees.

Conditions did not improve on Saturday June 21st, with the core of heat shifting east. A high temperature of 102 was observed by mesonet stations in the city of Watertown, as well as at the South Dakota State University mesonet station at the Redfield Municipal Airport. Heat index values Saturday would top out at 118 in the town of Stratford and 116 in the town of Castlewood.

The heat was a little less intense Sunday, June 22nd. While weather stations in the area failed to top 100 degrees, heat index values of 113 degrees were observed in the town of Castlewood and 112 degrees in the town of Mellette.

Source: NOAA Storm Events Database, event_id 1272138. Narrative written by the NWS forecast office that issued the report.