1. You're playing "gunshot or firework?"
  2. You're at a rooftop party!
  3. It smells like hot garbage everywhere.
    Because there is hot garbage everywhere.
  4. You walk into a store for no other reason than to partake in free A/C.
    Suggested by @donnie
  5. You're hoping a train comes through the subway station just for the whoosh of stagnant, hot air. This grossness is outweighed by the ability to have a drink on a patio in the evening.
    Suggested by @abbyzeecee