Thanks Vic, that's really helpful.

I thought SoCal was sufficiently warm for these animals to brumate outdoors, as I've come across numerous people here who keep Russian, Hermann's, and Desert Tortoises outdoors all year long.

However, when I talked to the lady I mentioned in the original post, the one who successfully puts her Desert Tortoises in the garage for the winter months, it got me thinking that maybe I should provide another place for these guys.