dave the baker
Sous Chef
I don't know what part of SoCal Dave lives but depending on the region, such as mountains, deserts, or inner valley communities, extreme temp swings are very common.
I live near downtown Los Angeles and am very close to the coast so although we were in the high 80's during the day, overnight temps only dipped down into the low 60's only. We don't get the extreme temp variations.
Many homes in LA have water heaters in simple, non-insulated sheet metal enclosures attached outside of homes. This is very common.
My water heater happens to be located in the basement.
I live in the Poway valley of San Diego, about 8 or 9 miles from the water. RoadFix has a basement, which is quite unusual in SoCal. We didn't have one when we lived in Rancho Cucamonga (yes, there is such a place), or Pomona, near LA.