Bob-tx wrote:
In an ordinary refrigerator / top freezer, where is it the coldest; top
shelf or bottom?

Since warm air rises, it would seem that the bottom would be coldest,
but I have
heard that the top shelf is colder, but I don't know why that would be.

Does anyone know for sure, and why?

Thanks, Bob-tx

They've invented this thing called a thermometer.
It can actually answer the question for YOUR particlar case without
ambiguity.