Generally speaking, Arizona is the perfect place to camp in a hybrid camper. The deserts are perfect in winter and mountains in summer. Last January we scheduled a long weekend at the Catalina SP (North of Tucson) with the expectation that nights would be cold (possibly even at or slightly below freezing), but with daytime highs in the 60s.
Unfortunately for us, we caught the coldest spell that we've experienced during our 15 years (or so) of living in the Valley of the Sun.
As you can see in the pics, we woke to much colder temps than expected. I was prepared for upper 20's, but 17 degrees! We decided to tough it out, because it couldn't possibly get colder than that in the desert!
The second morning we woke and it was even colder (yes, that is 13 degrees).
I had not winterized the camper, since I didn't think the temps would get that cold. Because of that, we decided not to push the limits and cut our trip a day shorter than planned.
As you can see, the pups weathered the cold just fine (in our bunk, of course).
The camper survived the ordeal without any damage, but if we didn't have hookups, the on-board furnace would have never kept up. Overall we stayed plenty warm, but used the bunk heaters, furnace and 1 electric space heater to keep the interior in the upper 50s to mid 60s during the coldest part of the morning.
Fortunately the daytime highs were in the low 40's so we never experienced a prolonged hard freeze.