Garden Basics E3: Understanding Cold Hardiness Zones

Tips, Tricks

1. I'm in zone 5, almost zone 6, which indicates an average annual minimum low temp of -10 to -20 F. But it very rarely reaches ten below here, much less 20 below. It hit 5 below once this past winter, and that was a record low for that particular date. I can only recall it reaching 20 below once in my life, and that was so rare that they actually cancelled classes at Penn State that day because of it! (well, the wind chill was 60 below, so that was part of it) Ten below maybe twice in my life, if that? What gives??
2. 2016