The quote highlights the extreme coldness of the outside environment, suggesting it was intensely chilly. The phrase implies that even a lawyer, typically seen as a professional, would instinctively keep his hands in his own pockets to stay warm, emphasizing the severity of the cold weather.
It paints a vivid picture of an exceedingly cold day, using humor and exaggeration to convey just how cold it was. This depiction helps the reader imagine a scene where the cold affects everyone, regardless of their status or profession, making the setting feel both real and memorable.