My son is dating a gal from California - he grew up and lives in Seattle. A hot day for him is 80 degrees. (This morning our heat kicked on - I need to turn it down more!) She is moving to Phoenix. We told him he should wait for winter to move down there to acclimate a little bit.
He did draw the line though on her looking for a job in Chicago!
The way I explain Phoenix in the summer to northerners is:
Crank the wood stove up to high and then stick your head in it.
That is Phoenix in the summer. :-)