When the temperature is too high, I simply cannot orgasm.  The sex still feels good and I want to climax, but I can't.  Is there any logic to this?  Other than turn up the air conditioner, is there anything I can do differently?

While I don’t have a scientific answer for you, and there may not be a medical reason for this, I can think of a few psychological causes for this. Most likely, when you were very hot you were unable to have an orgasm and you blamed it on the heat, though it could have been some other reason entirely. Then the next time it was hot, you remembered what occurred the last time, and that made you worry that you wouldn’t have an orgasm again, and those worries made it a self-fulfilling prophecy. If that’s the case, I would suggest that you try several more times in the heat, trying to push aside any worries that crop up, and see if you can overcome this. If you can’t, then do as you said and simply turn up the air conditioner.

Another reason that this happens to you could be as a result of some physical aspect of making love when it’s hot. For example, let’s say that you started to sweat a lot. You then worried that your partner would dislike seeing you with so much sweat, and it’s that worry that is preventing you from having an orgasm. If something like that is true, the first thing I would suggest is that you ask your partner. Maybe he could care less, or may even find it adds to his arousal. Depending on his reaction, you could either try to forget about this fear, or once again, turn up the A/C. Luckily for you there is this practical solution available to solve this particular problem.