I never realized that any part of Arizona stayed that warm through the winter.
I assumed "far inland, clear dry skies => very cold winter".
The only time I visited, it seemed to be desert, which I thought cooled off fast. Or do you have a winter "rainy season" that holds heat in?
Someone suggested bolting hoops onto a raised bed so she could drape shade fabric, clear plastic film OR row cover material to keep off cabbage worms, depending on the needs of the moment. Maybe some floating row cover and/or plastic film would let you germinate another crop of something, which then wouldn't need as much warmth to grow out.
