With 5–7 months in a row where the average temperature is below freezing, all water in the soil and subsoil freezes several feet deep. In the colder parts of this climate, summer warmth is not enough to "thaw" (unfreeze) more than a few feet on the top of the soil, so there can be "permafrost"(soil that is frozen forever). When the ice melts in the summer, 2 to 14 ft (0.6 to 4 m) of soil can thaw, depending on the latitude and the type of soil. Some subarctic climates near oceans (such as southern Alaska and the northern edge of Europe), have milder winters and no permafrost, so it is easier to farm there.