“Chicago Tribune (Chicago, Illinois) – 28 Jun 1933
Heat of 100.17
(Pictures on Back Page.)
The warmest June that Chicago ever knew attained new temperature heights yesterday when the official thermometer registered 100.1 degrees at 3.25 p. m.
This mark made a new all time record for the month, The previous maximum was on June 7 of this year. That date is ¢carried on the weather bureau books with a maximum of 100, but actually the high then was 99.8 degrees. Never before 1933 did any June day see the mercury even approach ‘the century mark. In fact, 100 degrees heat is a rarity in Chicago in any summer month.”
The following year, June 28, 1934 was even hotter.
Illinois June 28 temperatures have plummeted since the 1930s.