The term blue norther(n) denotes a weather phenomenon where a rapidly moving cold front that causes temperatures to drop quickly 20 to 30 degrees with heavily blowing winds and that often brings with it precipitation followed by a period of blue skies and cold weather. Due to the flat lands in Texas, it is said that it is possible to see the cold front coming from miles away and one can actually watch the clouds that form the cold front as they engulf the blue sky.
What is peculiar to Texas is the term itself. The derivation of blue northern is unclear; at least three folk attributions exist. The term refers, some say, to a northern that sweeps "out of the Panhandle under a blue-black sky" that is, to a cold front named for the appearance of its leading edge. Another account states that the term refers to the appearance of the sky after the front has blown through, as the mid-nineteenth-century variant "blew-tailed norther" illustrates. Yet another derives the term from the fact that one supposedly turns blue from the cold brought by the front. Variants include blue whistler, and in Oklahoma, blue darter and blue blizzard. Though the latter two phrases are found out-of-state, blue northern itself is a pure Texasism. The dramatic effects of the blue norther have been noted and exaggerated since Spanish times in Texas. But that the blue norther is unique to Texas is folklore.
