I live 7000 feet up in mountains of San Bernadino,C A. some mornings between 6 am and 8 it feels like 40 to 50 degrees. When or at what temperature do rattlers come out of the hole?

As soon as they sense the earth is heating up; I don't know, around 8 or 9 am. They are cold blooded and sluggish when it is cold, that's why they are seen sunning on rocks in the hot sun.

Tick