It's a dry heat. You eventually get used to it.
Not during monsoon.
Anyway, I posed the question to the three major clubs in Phoenix and the response was as I expected.
The largest club is mostly cichlids. They have the manpower, but not the will to do an ALA convention.
The killifish club already holds an annual event in March that does get a lot of livebearer cross-over, but that group is really too small to host an ALA convention.
The planted tank club shares most of their members with the other two clubs.
Personally, I suspect San Diego or Los Angeles might be more fertile grounds.