At back side of the crank pulley, there is a tin that has " tabs" at the 3 and 9 o'clock positions. In the warmer ambient air temps the tin or crank pulley may be expanding few thousands and just enough for the tin to touch the back side of the pulley. The fix is to wiggle a screw driver between the two surfaces creating gap. If that doesn't resolve the issue then you are on track to remove the belt to locate the source which may be the fan lightly touching the shroud that involves a light shale and twist of the fan shroud and that may resolve it , but the correct way is to add or delete one or more of the round fan shim washers which I don't think you want to get involved with while you are in Fl.