Say you became a California resident on Dec 1. Then you need to report all losses during December on California return. This may not be 1/12 of all your losses in the tax year -- for the days during which the property was still your primary residence, you can't report any loss. Say you started renting out the property on Nov 1, then you would report 1/2 of all losses on California return, assuming that the rents of the two months are the same.
If you only started renting out the AZ property when you have become a California resident, then you can report all losses on your California return.
