August 19, 1976 began a sweltering late-summer heat wave. The high hit 98 degrees in Marquette, while the National Weather Service (NWS) to the west near Negaunee established a record high of 95 degrees. The temperature soared to 92 at Ironwood, and 94 the next day. Marquette touched 93 on both the 20th and 21st. A huge, hot upper-air ridge built over the central U.S. and helped produce the heat (Image 1 above). The ridge was beat back by a cool front for a few days. Then the heat came back in full force by the 24th. Highs reached into the 80s and 90s the next few days, with a record-setting 98 on August 27, 1976 in the City of Marquette.
The next cold front meant business. It blasted through the area bringing a substantial cool-down. On August 29, the high only reached 54 degrees in Marquette. Early the next morning, the temperature plummeted to 31 at the NWS--the coolest August temperature on record. There were even reports of a few flurries in the highlands west of Marquette. This was a sign of things to come. Over the next five months, cold air would set records for both intensity and duration over a good share of the country.