After last year's extraordinarily mild December, the warmest on record by a wide margin (13.3 degrees above average), December 2016 fell back to earth, 0.8 degrees above average. Through 12/21 the month was two degrees colder than average, but then the jet stream reversed itself and temperatures were seven degrees above average during the last ten days of the month, pushing the month into the above-average column - the eighteenth month in a row with above average temperatures. With every month of 2016 experiencing above average temperatures, it was no surprise that the year was one of the mildest on record, ranking fourth (joining 2015, 2012 and 2010 in the top 10). Here are a few other observations:
- Wintry conditions took hold from 12/9-12/20, with temperatures five degrees below average. This included the winter's first measurable snowfall (0.4" during the evening of 12/11) and first snowfall of one-inch or more (2.8" during the evening of 12/17). Two days had highs below freezing (and four other days had highs between 33° and 35°). And the low of 17° on 12/16 was the coldest reading in December in seven years. That day's high/low of 27/17 made it one of the five coldest days of the entire year. And while last December was the first to have no reading of 32° or colder, this December had 11 such days (which is fairly typical).
- Heading into the last week of the month it looked like this might be the first December since 2005 to have no temperatures in the 60s, but then the high reached 60° on 12/27.
- After having the wettest November in ten years (5.41"), December reversed course and was the driest in ten years (2.89"). Despite this below average amount measurable precipitation fell on twelve days. For the second year in a row the year's total precipitation was well below average (42.17" vs. the average of 49.94"; 2015 had 1.20" less precipitation than this year). The last time there were comparable back-to-back dry years was in 1985 and 1986.