Anyone that gardens has checked a zone map and knows which gardening zone they live in. Most people don't realize the importance of knowing whether you live in a micro-zone.
My house is in zone 10, but I live one block from the Gulf intercoastal waterway up on top of a bluff. As a result of the warming effects of the Gulf water my actual gardening conditions are more similar to zone 11.
Other geological features can affect your zone. Living in a valley or on a north facing slope can make your temperatures colder.
Many times we find out about our micro zone through trial and error. It is much better to learn your gardening information from your neighbors; people that can give you the benefit of their years of experience.
Next, I would talk to a cooperative extension agent to see if there is a master gardener volunteer in your area. Then I would see if one of your state universities has published books on gardening in your area. One of my go to books is "Vegetable Gardening in Florida" by James Stephens of the University of Florida.
One zone can make a world of difference in whether the plant varieties you choose to plant in your garden thrive or die untimely deaths. I learned the hard way and now I buy plants that can tolerate the heat of zone 11.