It all depends on their winter snowfall; having family in Flagstaff, I have been up there during all parts of the year, and the winters seem to be different every year. One year they get a ton of snow, and it sticks around late into the Spring, other years, they get very little snow. About 5 years ago, while heading up I-17 from PHX, ran into a blizzard in March.
I just recommend monitoring the weather throughout Dec/Jan/Feb.
Victory Motorcycle Club / SOCAL Freedom Riders Chapter
Southern California Motorcycle Association Member
USN VET 1986-1996
Operations Specialist First Class (SW)
2012 Victory Cross Country Tour