Frigid--The concept of the frigid soil tempe rature regime and other soil temperature regimes listed below are used chiefly in defining classes of soils in the low categories. A soil with a frigid regime is warmer in summer than a soil with a cryic regime, but its mean annual temperature is lower than 8°C, and the difference between mean summer and mean winter soil temperatures (June-July-August and December-January-February) is more than 5°C either at a depth of 50 cm from the soil surface or at a densic, lithic, or paralithic contact, whichever is shallower.

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