This United States Army manual, Training Circular TC 21-3 Soldier's Handbook for Individual Operations and Survival in Cold-Weather Areas September 2025, provides aid for Soldiers in cold climates. To develop successful cold-weather field techniques, application training and operational experience are also necessary. Additional information can be found in ATP 3-90.97 and TM 4-33.31. The principal audience for TC 21-3 is any Soldier operating in cold weather. Military history of operations in northern areas record that a Soldier's success or failure is measured by their regard for the dominant characteristics of a cold-weather environment. TC 21-3 is applicable to the Active Army, Army National Guard/Army National Guard of the United States, and United States Army Reserve unless otherwise stated.