We're here in AZ and I can tell you, with temps over 100F this week, no ALO will expect you to wear a jacket and/or tie! Good gosh - you'd pass out from the heat! ha! My recommendation is business casual.
DD has her interview next week here in AZ as well and her ALO told her to wear business casual as it is an interview. This can be widely interpreted but a safe bet is a sport coat, collared shirt with tie for gents; a jacket with dress slacks/skirt and blouse or a jacketed dress for gals. Dress shoes as appropriate with no stilettos or sandals. Unless the interview will be held outside, one who lives in AZ won't roast too badly on the way in...besides, we are in a cooling trend, right now it's only 98 degrees outside. Yay, it finally feels like Fall.
Just like everyone already said, be yourself, no BS; knock it out of the park! Good luck with your interview.