It's been below freezing here. A few years back we had a couple weeks of sub-zero (C) weather--at night, of course. I lost many plants that winter. Generally, this is as cold as it gets. For February, the thirties is unusually low. As you know, summers in the Sonoran Desert can be unbearably hot. Last July, we hit 116 in Tucson; even higher in Phoenix. I grew up on the mid-Atlantic Coast, where winter temperatures can fall well below zero with ice and snow abounding. For several years, I lived in the mountains of Pennsylvania, where snowfall reached a total of 17 feet one winter.