Gardening Planting zones such as the USDA ones or the AHS ones can be useful, but no national map can take account of the local microclimate that your garden or yard is subject to.
You need to have half an eye on the hardiness zone for your area and then to experiment with plants that are rated for lower zones until you find which plants die.
The most widely referenced gardening planting zones are the US Department of Agriculture ones. These are based on average minimum temperatures.
Minimum temperatures are important but there are other factors that are important deciders in whether or not you can grow specific plants. These include the number of days that the temperature is below specific values, the probability of below average temperatures, the maximum temperature and reliability of snow cover.
The USDA hardiness zones use different temperatures from European planting zomes. Australian hardiness zones are different again. The American Horticultural Society (AHS) has different zones again for North America that take some of these other factors into account.
The nonsense of just using USDA hardiness zones is obvious once you consider that southern Alabama and the Shetland Isles off the west coast of Scotland are both on the USDA 8/9 border because they have the same average minimum temperatures. That is the only thing they have in common and it would be ridiculous to compare the two climates with Alabama being on average 200C, 700F hotter than the Shetlands.
The AHS climate map is more useful even in North America than the famous USDA map.
The USDA map is shown below. The AHS map is subject to copyright but here is a link to it. The AHS map is far more useful than the USDA one. Buy your own copy from the AHS site, here.
Your microclimate has a major impact on the plants you can grow, I live on a hill near Cork city. The temperature in my garden is an average of 20C, 30F cooler than it is at the bottom of the hill. Spring and summer flowering plants are usually two weeks later than Cork city and autumn arrives two weeks early.
