I remember some cold COLD early mornings growing up in Tucson. Easily in the 20's and occasionally it would dip into the teens. But those were the really clear days/nights and it would always make it into at least the 60s by mid-day...
But, hey, it was a DRY cold too, and that seems to make just as much difference as with heat. I remember days at 15 below when I was living in the Colorado Rockies that never felt NEAR as cold as high teens in Rochester, NY...
When you say you're using the 28-70, is that the kit lens for the A7 used on an APS at more like 42-105? Or is it some 28-70 equivalent???
Cute shots BTW!
-Ray