The hum of an AC compressor
All this talk about heat makes me think of sounds that psychologically cool us off. One of the radio stations was interviewing people that were hanging out around the fountain pond in downtown. They were saying just being around the water, and hearing the splashing was enough to cool them down. Not sure if it was any cooler boy the pond and fountains..due to evaporative cooling...but it was certain that the people hanging out around there were beating the heat in their mind.
One of the sounds that I have always liked is the sound of a running air conditioner. The subdued hum of the compressor, combined with the "white" noise of the fans is enough to make me feel very relaxed. Just like the fact that the people at the fountain pond weren't wet, I don't even need to be in the air-conditioned space to feel the comforting effects of the air condioner...just be able to hear it, to enjoy a little bit of it's effect. I am not sure if this is because the noise means comfort is not far, or if it's because the sounds and AC unit makes is naturally pleasing to the human mind.
...as for now, I'm going to go upstairs and relax beside my old Sears Coldspot window unit and wait for the cold front to move through tomorrow!