A sudden downpour that lashed downtown Chicago on Thursday afternoon did a bit to suppress the heat.
The city's official temperature, taken at O'Hare International Airport, reached 103 degrees shortly after 2 p.m. About 90 minutes later, O'Hare was reading 90 degrees.
Downtown Chicago's temperature fell about five degrees.
Mercury hitting 103 degrees was a new record for July 5, trumping the 102 degree bar set in 1911. The next mile marker to beat was 105 degrees, Chicago's all-time record.
The heat, which has already proven fatal, isn't expected to subside until Sunday.
An excessive heat warning is in effect through Friday for the Chicago area. Thursday temperatures could reach the record 105, according to NBC Chicago meteorologist Alicia Roman, with heat index values as high as 115.
Friday sees another dangerously hot day with highs near 101 and heat indices as high as 105, the National Weather Service predicts.
Records could be broken Friday too. The 99-degree record was set in 1988.
Stifling Independence Day temps tied a record of 102 degrees first set in 1911. It was only the second time since records have been kept when Fourth of July temperatures reached higher than 100 degrees.
Conditions were so oppressive that Columbus Drive buckled clear across the roadway near Roosevelt Road in Chicago's South Loop, creating a bump nearly five inches high.
"I never expected it to tell you the truth," one passerby told NBC Chicago. "I guess somebody must have had an accident there, looks like a piece of a car. Never seen anything like it."
Columbus has since closed at Balbo to prevent further accidents. Outside of Chicago, Golf and Roselle roads also reportedly buckled in Schaumburg.