our frost depth here is two feet. most winters it will not get that deep of a freeze. if there is snow cover that really helps insulate the ground and makes it much nicer for the garden plants if they don't have to contend with the frost heaving. this year i don't have many transplants to worry about, but after some winters i can find plants just laying on the surface after they've been frost heaved out of the ground.
So curiosity got me......all of VA and South into GA, etc, only 6 inches. That varies with weather, exact location, ground type, etc. I cannot remember having ground freeze more than an inch. And that only maybe once or twice. I'm sure the water has a lot to do with our warmer soil. Now I can rest on that issue.
yes, there's quite a difference in frost depth, note that two feet would be the average... when i was living up north that was like you all are talking about, much more and even then it would go deeper some years.
Where you live is a dramatic factor for gardening -- and raising livestock! -- with what works or not. I cannot imagine living where ground is frozen a foot or two, or three