Which calendar day is arguably the ‘hottest’ day of the year? Making a good case is, July 28th.
For the date, July 28th, the hottest temperature ever recorded was 101° in 1930.
While it is not the hottest temperature ever for the city of Indianapolis (106° officially set July 14th and on numerous other dates) and (107° unofficially taken prior to the airport being recognized as the official record station) it has produced the most 90° plus days on record.
Dating back 149 years, the city of Indianapolis has recorded 3122 days of 90° plus high temperatures. July 28th has produced 46 of them, the most of any other calendar day. 3 of those reports topped 100°.
Topping 100°, well that has happened 72 times on record. Several days have reached 100° on 3 occasions, including July 28th.