From NWS
1976: Unseasonably warm weather peaked on September 6-7 with highs generally in the 90s across about the western two thirds of Iowa and some triple digit temperatures reported in the northwest. On the 6th reported highs ranged up to 101 F at Onawa and Sanborn, 102 F at Sibley, Sioux Center, and Sioux City, and 103 F at Le Mars. Amazingly, a strong cold front swept across the state a couple of days later and by the morning of the 10th frost was reported across the lowlands of Iowa with freezing temperatures at a few locations. In fact at Sibley the high of 102 F on the 6th was followed by a low of 33 F less than four days later on the 10th.

1969: A severe thunderstorm struck northwestern and central Iowa with 85 mph wind gusts producing extensive damage at Ames and large hail falling from Fonda to Rockwell and from Ames to Huxley and Slater. Hail stones as large as 2 inches in diameter were reported and crop losses were in the millions.

1939: Very hot weather sent the temperature all the way up to 107 F at Logan tying the all-time Iowa September mark which would be tied again just the following day. Other high temperatures on the 6th included 106 F at Little Sioux, 104 F at Shenandoah, 103 F at Fort Dodge and Sioux City, and 102 F at Atlantic, Belmond, Carroll, and Guthrie Center.

1939: An unseasonably strong heat wave settled across Iowa from September 3-7. Des Moines set its all-time September record with a high of 101 F on the 3rd, reached 100 F on the 6th, then tied the record with 101 F again on the 7th. These are the only occasions of triple digit heat on record at Des Moines in the month of September. Also on the 6th Logan tied the all-time Iowa September record with a high of 107 F, which would be tied again just the following day. Other high temperatures on the 6th included 106 F at Little Sioux, 104 F at Shenandoah, and 103 F at Fort Dodge and Sioux City

6 September 1840 → The first official weather observation in Canada was taken at Kings College, at the University of Toronto by members of the British Royal Artillery. 6 September 1972 → The first tropical cyclone landfall in California since 1939 was Tropical Depression Hyacinth on this date, just north of San Diego. 6 September 1996 → Category Three Hurricane Fran made a direct hit on North Carolina with 115mph winds. Six people died and up to 16 inches of rain fell. The storm caused $2.4 billion damage in North Carolina just two months after the state had been hit by Category Three Hurricane Bertha.

Posted under Weather History