The day of the winter carnival is described as "battleship gray". Interpretation

Battleship gray would describe the sky..... the dreary, winter atmosphere. Gene uses the color gray as a descriptive adjuective throughout the text.

We were sitting in our room, on either side of the single large window framing a square of featureless gray sky.

The sky is an empty hopeless gray and gives the impression that this is its eternal shade.

The Saturday was battleship gray.