Devastating freeze for the Valley as historic cold weather system moves in | Phoenix News

Lows in the high country will hover around zero, but with the wind chill, it will feel much colder, closer to 30 below. There’s actually a wind chill warning for Flagstaff and the rim country. Here in the Valley, there is a freeze warning. The forecast low in town is 30 degrees, but outlying areas could get down to 20.
...
This is some of the coldest weather we’ve seen in Phoenix in years. Temperatures could approach those of 2007's killing freeze -- when Sky Harbor got down to 29 degrees -- but with the wind, it could feel even colder.