Leaving your air conditioner running on a night like this can actually save you money. Often it's okay to give your system a break and open the windows.
Air Conditioner technician Les Sutton notes, "Fifteen percent humidity I think you know, it'd probably be a point to where that's good." But if you want to pay lower utility bills, that rule changes. On high humidity days it's best to rely on your air conditioning and fans to keep cool indoors." Sutton says, "let your AC do what it's supposed to do."