“The 2023 map is based on 30-year averages of the lowest annual winter temperatures at specific locations, is divided into 10-degree Fahrenheit zones and further divided into 5-degree Fahrenheit half-zones. Like the 2012 map, the 2023 web version offers a Geographic Information System (GIS)-based interactive format and is specifically designed to be user-friendly. Notably, the 2023 map delivers to users several new, significant features and advances. The 2023 map incorporates data from 13,412 weather stations compared to the 7,983 that were used for the 2012 map.”
It is available online at https://planthardiness.ars.usda.gov/
FWIW my corner of the planet has moved up a full zone, from 5b to 6b. If this keeps up I’ll be able to hybridize pineapples pretty soon!