December 2012 was mostly warmer than normal. Precipitation was near to above normal over the western and northern areas, while the southeast had mostly below normal precipitation.
The first eight days of December followed the pattern of much of October and November, that is, mostly dry with above normal temperatures. But that changed abruptly on the 9th, as a deep trough of low pressure and strong cold front brought snow and drastically colder temperatures to the state. Temperatures recovered slowly from well below normal on the 10th to normal or above on the 11th through 13th. The next storm arrived early on the 14th with more moisture than the previous storm, resulting in widespread snow and rain across western and central areas of the state. Another storm quickly moved in on the 15th and departed early on the 16th with moderate snows over the west and north high terrain. Yet another storm quickly arrived on the 18th and continued into the 19th with high winds, snow and much colder temperatures. A break from the active weather from the 20th through 23rd was followed by the 5th significant storm of the month, just in time for Christmas Eve into Christmas Day. Another storm brought relatively minor precipitation to the state on the 27th and 28th. The active pattern delivered one more significant storm this year, on the 30th into the 31st.