While the USDA map should not be regarded as a precise document of climatic charting, it does give us a rough idea of minimum temperatures for a given area.

However, you should understand that zone 8 Florida is much different from zone 8 Oregon and some plants that will live in Oregon's zone 8 will likely not make it in a south eastern zone 8. The map also does not take into account micro-climates. A micro-climate can exist in any given area. Micro-climates are usually a few degrees warmer than surrounding areas.

Below are the zones and their temperatures.