The cowboys had lived for months under the great bowl of the sky, and yet the Montana skies seemed deeper than the skies of Texas or Nebraska. Their depth and blueness robbed even the sun of its harsh forceöit seemed smaller, in the vastness, and the whole sky no longer turned white at noon as it had in the lower plains. Always, somewhere to the north, there was a swath of blueness, with white cloads floating in it like petals in a pond. 537

-McMurtry, LarryJeff
  Lonesome Dove, ch.93.