How Far Down Does the Ground Freeze in Winter

The line varies by latitude, it is deeper closer to the poles. Per Federal Highway Administration Publication Number FHWA-HRT-08-057, the maximum frost depth observed in the contiguous United States ranges from 0 to 8 feet (2.4 m). Below that depth, the temperature varies, but is always above 32 °F (0 °C).

At what point does the ground freeze?

When the temperature of the ground drops below 0° Celsius (32° Fahrenheit), it freezes.

Does the ground freeze under snow?

A thick layer of snow acts like a blanket so that heat does not leave the ground (Figure 3). Only a thin layer of ground will freeze under a thick layer of snow.