Even the Nazi’s provided their prisoners with blankets. It’s mentioned in Night, it’s mentioned in The Men with the Pink Triangle. The Nazis took away the blankets when they felt like being especially sadistic.

After the soup, we gathered between the bunks. The veterans told us: "You're lucky to have been brought here so late. Today, this is paradise compared to what the camp was two years ago. Back then, Buna was a veritable hell. No water, no blankets, less soup and bread. At night, we slept almost naked and the temperature was thirty below. We were collecting corpses by the hundreds every day. Work was very hard. Today, this is a little paradise. The Kapos back then had orders to kill a certain number of prisoners every day. And every week, selection. A merciless selection.. Yes, you are lucky."

From Night