Merlin

Is there a limit to the maximum air temperature that is possible (as measured at a standard height above ground in a Stevenson screen)? In various posts I've seen comments regarding humidity and warmer less dense air rising that sound as if they place a maximum limit to naturally occurring air temperature. Is this so? Does this mean that temperatures of 60+ degrees C are just impossible? If there are limits to the possible air temperature, will the limits change from one location to another depending on geography. I'm guessing that altitude, slope and proximity to an extensive water body may influence limits?