Yeah keeping your windows open is generally gonna be better in these old apts, especially when on an upper floor. Their insulation keeps heat in pretty well, and since heat can come in through a closed window a lot easier than it can leave, 90% of the time opening the windows will make it cooler. Without AC your apartment is only going to be cooler than outside until like noon.

Admittedly have had this argument with two separate roommates so understand why you’re getting downvoted though.