Chicago's recent round of late hot temperatures aren't just unusual, they're unprecedented.
According to the National Weather Service, there has never been a heat wave this long and this hot recorded this late in the year in the city.
Chicago has never seen five consecutive days with high temperatures at or above 92 degrees this late in the season. The previous streak of four or more days in a row was seen Sept. 16-19 in 1955, according to the NWS.
The hot temperatures broke numerous records over the last several days.
Saturday's high of 95 degrees tied for the hottest day of 2017, setting a record for the latest in the year the hottest temperature of the year was recorded in Chicago.
The latest such a temperature has been recorded was on Sept. 14 in 1893, 1915 and 1927.
Here's a look at the records that have been set so far:
Wednesday: High of 92 degrees; broke record of 91 degrees set in 1931
Thursday: High of 94 degrees, broke record of 92 set in 1970
Friday: High of 94 degrees again broke a record of 92 set in 1956
Saturday: 95-degree high breaks record of 91 degrees set in 1937
Sunday: 93-degree high breaks 1891 record of 91 degrees
Monday: 92-degree high at O'Hare Airport breaks record of 90 degrees set in 1933
But a cool down is expected soon.
Tuesday will see the week's final warm and humid day with highs in the low-80s. By Wednesday, temps dip into the mid-70s and by Friday, highs will sit in the upper-60s.