The updated USDA zone map has been released! Although some areas didn’t change, many places did see a shift. It can be a little nerve-wracking to hear about a big change to our gardening lives; USDA zones are a vital part of the way we understand our spaces and choose plants. I’m here to tell you not to worry too much, this change isn’t as disruptive as it may feel. For instance, my garden used to be listed as 5b and now it is 6a. My existing plants can stay and on the bright side, I might be able to confidently grow things I haven’t tried before.
The last update to the USDA zone map was in 2012 and used data from roughly eight thousand weather stations. This new update uses over thirteen thousand! The map is more accurate than ever.
Zones are determined by the average lowest temperature an area receives each year. Using an average, instead of just the lowest recorded temperature ever, provides a reasonable guess at what our gardens will actually experience year after year.
The 2023 USDA zone update uses data collected over the past 30 years and, of course, includes the 11 years since the last update.
This does not impact the zone listings on the plants you buy. The temperature ranges of their hardiness are the same, it’s only the boundary lines of the USDA zone map that have changed. If your zone changed, it was in name only. You’ve been able to grow more tender plants for a while now.