Historical clue formulations

• Scorcher — 2022-08-19
• Scorcher — 2020-08-26
• Scorcher — 2017-02-07
• Definitely a day to run the A.C. — 2013-09-30
• Day during the dog days — 2012-07-22
• Definitely a day for air-conditioning — 2008-11-24
• Knee-slapper — 1999-07-16
• Knee-slapper — 1998-10-10