Although I am in the Phoenix area now I was born in Chicago and lived there for 27 years and then moved to California and then to Arizona about 6 years ago. The summers here are very hot but with air conditioned homes and cars and at work it is tolerable. On weekends do your running early before the worst of the heat hits. As been said it's a dry heat but so is the oven. You tend to get used to it but I will admit I am very happy to see fall come along. I prefer Arizona to California and Illinois for a bunch of reasons but that's just me.