Water has some amazing properties. It is one of the few substances that expands both as it goes from a liquid to a vapor, and as it moves from a liquid to a solid. It’s the transition from a liquid to a solid that has people concerned with the number of freeze/thaw cycles. That expansion can damage roads and foundations. It can cause heaving of plants out of the soil, exposing the roots to the damaging wind and cold. A freeze/thaw cycle is the number of times that the temperature moves from above freezing to below freezing. Not surprisingly, Kansas has more freeze/thaw cycles than Mississippi where winter temperatures tend to be milder. But it might surprise you to know that we also have more than North Dakota. That’s because when it gets cold in North Dakota, it can stay cold for quite some time. Remember, it has to get above freezing for it to be a cycle.
Mary Knapp, Weather Data Library