Historical clue formulations

• When squirrels may thermoregulate by splooting — 2025-07-25
• When air-conditioners really hum — 2020-05-12
• When many fans come out — 2016-02-12
• Stretch in the 90's, say — 2007-02-03
• Summer weather phenomenon — 2004-01-20
• Dog days phenomenon — 2002-03-19