How did extreme cold affect soldiers during the Battle of the Chosin Reservoir?

During the Battle of the Chosin Reservoir, extreme winter weather—with temperatures dropping as low as −34 °C (−30 °F)—severely impacted soldiers on both sides of the conflict.1

The environmental conditions caused significant casualties and operational challenges:

• Casualties: The cold was a major cause of incapacity and death. The 1st Marine Division suffered 7,338 casualties due to the cold, compared to 4,385 combat-related losses. Similarly, Chinese Ninth Army Group forces experienced high numbers of deaths and incapacity from the freezing temperatures, which ultimately contributed to their troops becoming ineffective.1
• Operational Impact: Soldiers struggled to maintain basic functions, necessitating the use of warming tents for sleeping and eating. The extreme cold also affected equipment and logistics, complicating the movement of troops and supplies through the mountainous terrain.12

The harsh climate defined the brutal nature of the campaign, forcing the X Corps to conduct a difficult retrograde movement to the coast to escape the freezing conditions and enemy pressure.12