Flew there for nearly 2 years. The weather is very good...and yes, it is hot, especially in Tuscon.
However, the opportunity to get time in actual IFR conditions is virtually non-existent compared to other areas.
I was grounded for nearly 2 weeks for a night flight due to monsoons in the fall; otherwise very few weather disruptions.
There are various types of airspace (B, C, D, and uncontrolled), which gives you good experience. Where you learn to fly usually makes you comfortable in that particular airspace; students from LA may feel more comfortable in complex, high density airspace and not uncontrolled, less dense areas. Arizona has, in theory, nearly all types. Depends of course on your instructor, and where you spend your time.
Have fun!