A group of new arrivals in Antarctica and a group staying a second consecutive year were observed over a period of one year. Differences of cold acclimatization in finger sensitivity was demonstrated which were lost within 6 weeks. There was no difference in resting finger temperature between the groups, but there was a significant fall in temperature over the year. It was concluded that some forms of acclimatization to cold occur only after a greater degree of cold stress than do others. Second year men showed the greater immunity to frostbite under the experimental conditions, but this was not proved statistically. The addition of drift snow to the ‘cold’ wind doubled the numbness induced in the finger. Under ‘very cold’ conditions drift increased finger numbness over six times. Provided sufficient time is spent outdoors, the outdoor temperature is the more important for cold acclimatization, regardless of comfortable indoor temperatures.