Cold-weather warfare
Post World War II: The Battle of Chosin Reservoir was a stark example of cold affecting military operations in the Korean War. There were many cold injuries and malfunctions of materiel, both vehicles and weapons.
The Sino-Indian War was a Himalayan border conflict between China and India that occurred in 1962. India initiated a Forward Policy in which it placed outposts along the border in 1961.  China launched simultaneous offensives in Ladakh and across the McMahon Line on 20 October 1962. Chinese troops advanced over Indian forces in both theaters. Much of the fighting took place in harsh mountain conditions, entailing large-scale combat at altitudes of over 4,000 metres (14,000 feet). Many troops on both sides succumbed to the freezing cold temperatures.
Argentine troops suffered from cold-wet conditions, holding positions in the 1982 Falklands War.
The Siachen conflict is a military confrontation between India and Pakistan over the disputed Siachen Glacier region in Kashmir. The conflict began in 1984 with India's successful Operation Meghdoot during which it gained control over all of the Siachen Glacier. A cease-fire went into effect in 2003.

Historical lessons learned: Paton offered a 2001 overview of human factors pertaining to cold in military operations. The understanding of cold injuries evolved in the 19th and 20th centuries; understanding of the causes and treatment of frostbite and trench foot improved. In the Sino-Japanese War, the Japanese learned the importance of foot care, keeping feet dry and warm with replacement socks. In World War I, doctors realized that trench foot was a prolonged exposure to cold, wet conditions on the feet, which were exacerbated by the use of tight puttees, bandage-like leg wrappings.
The Soviet invasion of Finland during the Winter War showed the power of asymmetric warfare on the Finnish side, where small units were able to cut the road-bound Soviet invading troops into segments, like firewood, and vanquish each segment. The small units arrived silently on skis or with light artillery pulled by reindeer over frozen, untracked terrain, using winter conditions as an advantage. Although the Soviet Union gained territory from the Finns, it was at the cost of 200,000 fatalities against 25,000 on the Finnish side.
The German invasion of the Soviet Union induced more than 250,000 cold injuries in one year. The French Army occupying the Maginot Line experienced 12,000 cold injuries. Experiences from the disastrous 1941 German advance on Moscow in winter conditions led to the 1942 Taschenbuch für den Winterkrieg ("Pocket book for Winter War"), which highlighted ideal approaches to handling winter, but acknowledged that improvisation in the field would be necessary when supplies were lacking. The Soviet troops in that period had felt-lined boots and quilted uniforms, but the Germans continued fighting in their summer uniforms.

German handbook: The Taschenbuch für den Winterkrieg manual contains sections on the influence and duration of winter, the seasons of mud and thaw, preparation for winter warfare, winter combat methods and maintaining morale, including the use of reading material, lectures, movies, and "strength through joy" exercises. Other sections cover marches, the maintenance of roads, winter bivouacs and shelter, construction of winter positions, camouflage and concealment, identification of the enemy, clothing, rations, evacuation of the wounded, care and use of weapons and equipment, signal communication, and winter mobility. The manual was designed to provide information at the officer level for indoctrination of troops via the non-commissioned officer ranks. The scope of the manual is to train troops in the following areas:

Protection of personnel, vehicles and weapons against snow and cold
Training personnel to be hardened against the conditions encountered and able to improvise shelter from found materials
Mobility on skis, winter roads, ice crossings, and conversion of wheeled vehicles into tracked versions
Construction of positions and obstacles in frozen terrain
Combat in deep snow and severe cold
Some highlights include addressing:

Human factors – Providing the right level of clothing to maintain agility and avoid overheating. Maintaining a slow, steady marching pace to avoid chilling down in the wind. Boosting morale with up-to-date newspapers from home and nearby areas. Providing improvised shelters and bivouacs. Hygiene, emphasizing cleanliness.
Mobility – Setting up and maintaining winter roads and trails. Warming up engines for reliable starting.
Positions and fortifications – Using logs and snow as materials to provide trenches and gun emplacements.
Care of equipment – Keeping equipment dry, when possible, and substituting low-temperature lubricants for oils and hydraulic fluids.

Soviet experience: The Soviet Army learned from its 1939–40 Winter War experiences and the 1941 German advance on Moscow. The high command realized that it must prepare entire divisions for winter warfare in 1942, beginning with warm uniforms, winter equipment (skis, etc.), and training for winter operations. Analysis of previous experiences resulted in a series of manuals that covered flight, engineer, and combat arms operations in winter. Issues covered included:

Flight operations – Reduced daylight, snow drifting, cold temperatures impeded the added need for air transport.
Engineer operations – Engineer troops build new roadways, airfields, water crossings, and encampments with water supply. They destroy obstacles, requiring engineering equipment. Regular troops entrench tanks, construct tank obstacles, and build simple shelters.
Combat arms operations – Addressing the German methods of defense with automatic weapons strongholds, supplemented with mines, wires, and anti-tank obstacles. Against these, the Russians used coordinated massed fire.
In his 1981 paper, Fighting the Russians in Winter: Three Case Studies, Chew draws on experiences from the Allied-Soviet War in Northern Russia during the Winter of 1918–19, the destruction of the Soviet 44th Motorized Rifle Division, and Nazi–Soviet Warfare during World War II to derive winter warfare factors pertaining to military tactics, materiel and personnel:

Tactics – Defensive positions are highly advantageous because of the ability to maintain warmth and protection, compared to attacking in extreme cold. Mobility and logistical support are often restricted by snow, requiring plowing or compacting it to accommodate wide-tracked vehicles or sleds. Infantry movement in deep snow requires skis or snowshoes to avoid exhaustion. Sound carries well over crusted snow, diminishing the element of surprise. Explosives are useful for excavating foxholes and larger shelters in frozen ground. Attacking field kitchens and encampments deprives the enemy of food and shelter. Rapid removal of the wounded from the battlefield is essential to their survival in the cold.
Materiel – Weapons and vehicles require special lubricants to operate at low temperatures. Mines are unreliable in winter, owing to deep snow that may cushion the fuse or form an ice bridge over the detonator.
Personnel – Proper winter clothing is required to maintain body heat and to avoid such cold injuries as frostbite. Troop efficiency and survival requires either making use of available shelter or providing portable shelter.

Land operations: Operational factors encompass planning for the climate and weather in which military operations are required with snow, ice, mud and cold being the primary considerations. Military tactics, materiel, combat engineering and military medicine all require specialized adaptations to the conditions encountered in cold weather.

Cold and mountainous regions: In its 2016 "Mountain Warfare and Cold Weather Operations" manual, the United States Army defines cold regions as "where cold temperatures, unique terrain, and snowfall have a significant effect on military operations for one month or more each year." It describes regions that are either severely cold or moderately cold, each comprising approximately one quarter of the Earth's land mass.

Severely cold – Where mean annual air temperatures stay below freezing, maximum snow depths exceed 60 centimetres (24 in), and ice covers lakes and rivers for more than 180 days each year.
Moderately cold – Where the mean temperatures during the coldest month are below freezing.
The manual also delineates the principal mountain ranges of the world, which lie along broad belts which encircle the Pacific basin and then lead westward across Eurasia into North Africa. Secondarily, rugged chains of mountains lie along the Atlantic margins of the Americas and Europe.

Weather conditions: Temperature, wind, snow, and thaw are the primary conditions that affect the winter battlescape.

Temperature: The U.S. Army groups cold temperatures using categories. The temperature categories are (with quoted summaries):

Wet cold – From 39 to 20 °F (4 to −7 °C). Wet cold conditions occur when wet snow and rain often accompany wet cold conditions. This type of environment is more dangerous to troops and equipment than the colder, dry cold environments because the ground becomes slushy and muddy and clothing and equipment becomes perpetually wet and damp.
Dry cold – From 19 to −4 °F (−7 to −20 °C). Dry cold conditions are easier to live in than wet cold conditions. Like in wet cold conditions, proper equipment, training and leadership are critical to successful operations. Wind chill is a complicating factor in this type of cold. The dry cold environment is the easiest of the four cold weather categories to survive in because of low humidity and the ground remains frozen. As a result, people and equipment are not subject to the effects of the thawing and freezing cycle, and precipitation is generally in the form of dry snow.
Intense cold – From −5 to −25 °F (−21 to −32 °C). This temperature range can affect the mind as much as the body.