We have been in AZ almost 2 full years now. Arrived in May of 2010. We love it. We live in East Mesa, nice location for starting rides as most rides either head North or East.
We love Tombstone & the area but, it is 4k' in elevation and winter is colder & they get snow.
The Phoenix area is 1200' give or take a few and the winter weather for the most part is great. December & January can be colder, 40's but this winter has been beautiful. High 40's at night high 60's & 70's daytime.
This past month has been mid to high 70's & into the 80's.
Now with all that said, there is not as much riding as you might think during the winter. Remember AZ has mountains that go up over 9k' on the roads. Everywhere that is 5k' or above is subject to being much colder & gets snow. For us no big deal, if there is no snow we go, just wear your heated gear. You can also head South towards Tucson, Tombstone, Bisbee, again once over 3k' heated gear makes it confortable.
We lived in N CA for 40 years, we will take AZ winter weather over CA, however if it is not raining CA has much better riding choices in the winter.
Don't know much about S CA, we aren't allowed there, at least that what Wrongway told us

Hope this helps