Certainly high atmospheric pressure and low air temps are the recipe for high power output yes.

Humidity though is a point for argument though.
Most people say its good for power but I don't think it is, I think it loses power.
Not easy to test I guess but for me, the water molecules take up valuable space that could have been filled with oxygen, so unless your gaining power from cooling the charge somewhat on an engine that is running too close to the knock line I don't see where any appreciable power increase is going to come from.

A Semi Interesting topic I know little about in all honesty.