Referring to the processes and landforms of any area with a tundra climate, or where frost processes are active and permafrost occurs in some form. Periglacial climates are arid, with temperatures below 0 °C for at least six months, and summers warm enough to allow surface melting to a depth of around 1 m. See Vandenberghe (2006) Geomorph. 54 on the transition from temperate to periglacial climates, and vice versa.

Periglacial processes include abrasion, freeze–thaw, nivation, and solifluction, and are responsible for the formation of new deposits, the alteration of existing unconsolidated deposits, and the modification of existing landforms by mass movement; see Millar (2005) Geomorph. 72, 1–4 and Braun (1989) Geomorph. 2, 1–3. Hall et al. (2002) PPG 26, 4 identify snow fall as a crucial factor in periglacial weathering. See Vandenberghe and Thorn (2002) PPG 26, 4 for progress in periglacial research.