From NWS
1997: Several rounds of severe thunderstorms produced very strong straight-line winds across Iowa. The first complex of storms moved from near Webster City east northeast into Wisconsin in just a few hours from around 11 pm on June 20th to 2 am on the 21st, producing wind gusts of 72 mph at Waterloo and 84 mph at Oelwein. The second cluster of severe storms entered southwestern Iowa shortly after 1 am on the 21st and moved rapidly eastward across southern Iowa before crossing into Illinois at around 5 am. These storms produced wind gusts of 66 mph at Red Oak, 81 mph at Knoxville, and 78 mph at Muscatine. Considerable damage was reported with the passage of both thunderstorm complexes and there was one fatality in Davenport when a tree was blown onto a tent.

1992: Unusually cold weather resulted in frost damage to crops in northeastern Iowa where Cresco recorded a low temperature of 35 F. Numerous daily record low temperatures were set across the area.

1988: Extreme heat affected Iowa on the first day of summer with temperatures soaring above 100 degrees at most stations around the state. The highest temperatures were recorded in northwestern Iowa including 105 F at Le Mars and Onawa, 106 F at Rock Rapids, 107 F at Hawarden, and 108 F at Sioux City which broke the all-time June record at that location. Elkader also set its all-time June record with a high of 103 F, while Des Moines tied its June record at 103 F.

1902: Unusually cool weather resulted in frost across portions of northern and western Iowa on June 21st and 22nd. On the morning of the 21st frost was reported from Spirit Lake over to Inwood and Sibley and south all the way to Atlantic. In most affected areas the frost was light and damage was minimal, but in a few low lying areas it was sufficient to freeze some crops and garden vegetables as reported by an observer at Spirit Lake. Low temperatures that morning included 37 F at Sioux Center, 36 F at Galva, 35 F at Guthrie Center, Sheldon, and Sibley, and 34 F at Fort Dodge and Larrabee.

21 June 1942 → The temperature reached 129 degrees in Tirat Tsvi, Israel. 21 June 1972 → An F3 tornado destroyed two homes and several businesses in Eloy, AZ. Also, an F2 tornado damaged several hundred homes from northeast Phoenix into Paradise Valley. 21 June 1987 → A tornado destroyed 57 mobile homes at the Chateam Estates trailer park northwest of Detroit, MI killing 1 person and injuring 6 others. Total damage was estimated at 1.7 million dollars.

Posted under Weather History