The USDA has updated plant hardiness zones, and despite last winter’s impressive cold, we’ve jumped up a zone (to 5a from 4b in 2012; the average low went up by 6 degrees)
Hardiness zones are a (partial) climate description that’s been in existence for a bit over a century, though the government didn’t get involved in it until the ’60s (At which point they proceeded to do so badly for a few decades). They use the average minimum winter temperature to determine the zone.
The current map can be found at usda.gov/ and is searchable by zip code. Here’s the current map for Montana:
Leave a Reply