Agriculture

Change in Plant Hardiness Zones, 2012 to 2023 in New York State

Change in Plant Hardiness Zones, 2012 to 2023 in New York State

I did some raster math to compare the 2012 plant hardiness zones to the 2023 plant hardiness zones. Most of the state was bumped up one zone, though many of the higher elevation areas remained in the same zones.
 
Interestingly enough, the Western Catskills actually fell back one or two colder Plant Hardiness Zones with the latest maps while the most of the state advanced to a warmer plant hardiness zones. The Western Catskills had a handful of particularly cold mornings in recent years, though maybe it's also an artifact of how PRISM krigings the temperature data.

I am also not convinced the area around Chautauqua Lake jumping from 5B to 6B or the Southern part of the Tug going from 5A to 6A. It's possible, but I am thinking it's a kriging artifact.
 
The 2012 Plant Hardiness Zones were really old data, 1975-2006, even at the time they were released. The 2023 Plant Hardiness Zones are 1990-2020, which is much more up to date. This is very problematic as the late 1970s were an exceptionally cold winters in New York's history. Old Forge hit negative 52, on February 18, 1979 which throws everything off.
 
Minor edits to this map on 11/7. Basically rather then comparing them using raster math, I did the contours separately for each year and then joined them against and did the math on the vector. Rethinking it, the later method is more accurate then with raster method, at least in comparison of other maps. That said, either way the result is very similar, we are talking about splitting fractions of a degree, which make the categories slightly different. Like anything, it's a matter of how you ask the question and the methods used.

USDA Plant Hardiness Zone

The USDA Plant Hardiness Zone Map (PHZM) is the standard by which gardeners and growers can determine which plants are most likely to thrive at a location. The most recent revision was prepared by the PRISM Climate Group at Oregon State University, and was released by USDA in 2012. Based on the average annual minimum winter temperature over a 30-year period, the map divides the country into zones representing a spread of 10Β°F (zones 1-13), each subdivided into two half-zones with 5Β°F spreads (e.g., zone 1a and 1b).

Data Source: PRISM Climate Group. USDA Plant Hardiness Zone, New York State.Β