Is it global warming? Probably not. But Westchester gardeners are now in a warmer planting zone, according to the just released 2012 USDA Hardiness Zone Map.
To find out whether your zone has shifted, you just type in your zip code.
The map—jointly developed by USDA’s Agricultural Research Service (ARS) and Oregon State University’s (OSU) PRISM Climate Group– now includes 13 zones and, compared to the 1990 version, zone boundaries have shifted in many areas. The new map is generally one 5-degree Fahrenheit half-zone warmer than the previous map throughout much of the United States.
The map uses data measured at weather stations during the 30-year period 1976-2005. In contrast, the 1990 map was based on temperature data from only a 13-year period of 1974-1986. This temperature data is not to be confused with climate change data. When climate change is studied, scientists look for trends in overall average temperatures over a much longer, 50- to 100-year period.
You can download your own copies of the map from the USDA website.