At the end of 2023 the USDA released a new updated hardiness map. The last map was released in 2012. Around half of the country moved half a growing zone warmer. Here is a link to the new interactive map on the USDA site, check to see if your area changed zones.
The map’s data is compiled of roughly 30 years of data. The new map includes data from 1991-2020. 2012’s map has data from 1979-2005. They determine the zones by taking the average annual winter lowest temps. There are 13 zones (1-13), the zones are in 10 degree increments. Then within those 13 there are sub zones (a, b) which gets the data down to 5 degree increments, a being the cooler and b being the warmer. The number of weather stations used to collect data nearly doubled, from 7,983 stations to 13,412 stations.
My area went up a sub zone from 6a to 6b. Did your’s change or stay the same?
Once you check your area on the new hardiness zone map, check your last frost date here. The last frost date will let you know when you can plant out without a high risk of losing plants to frost.