Whether it will be too cold is largely dependent on how well prepared you are.
In my opinion, no passage should be avoided.
Navigate your way over to the Arizona Trail Association's website at aztrail.org, become a member, and get access to all the information on the trail you will need. Armed with all that knowledge, you will then be able to make a informed decision about when to go and how to prepare.
Steward, Arizona Trail Passage 23c (Mazatzal Divide Tr, Barnhardt to Red Hills)
...he's got the Mazzic hands...