What does cold represent?

Jozef is constantly mentioning how cold it is. While the story does take place in central Europe, he is also away at war for over three years, so in that time there were breaks in the weather. However, the cold seeps into Jozef's circumstances and it is always present. The author never mentions a time when it's hot or even warm. Cold makes hard times seem harder, and Jozef's time in the war is characterized by one challenge after another with only very short periods of good in between.