The top graphic tells most of the story. Pretty much everywhere you see the brown shading it was the warmest December in the historical record. In some cases, it would have been in the top 10 warmest Novembers for that location as well. This follows on the 11th warmest November in the historical record, averaged over the Continental U.S. (CONUS). The graphic below shows the 121 year rankings (1895-2015) by state.
And it was wet both in December and November 2015, as you can see in the maps below.
You should be able to get why the mid-Mississippi Valley is under water right now.
Awww, I miss the orange croissant!
Continental U.S. Extremes
How extreme were the temperatures here in the U.S.? Here’s a sample of some of the weather summaries for December 2015 from some National Weather Service Forecast Offices:
Boston MA:
DEC...NUMBER OF DAYS HIGH >= 50...20...PREVIOUS RECORD 16 IN 1953. ... DEC...LEAST NUMBER OF DAYS LOW <= 32...6...PREVIOUS RECORD 11 IN 1911. DEC...WARMEST MONTHLY AVG TEMP...45.3...PREVIOUS RECORD 41.0 IN 2006. DEC...HIGHEST MONTHLY LOW TEMPERATURE...24...PREVIOUS RECORD 23 IN 2001. /THIS MEANS THAT NO DAYS DURING DEC HAD A LOW TEMP. BELOW 23/ DEC...HIGHEST MIN-HIGH TEMPERATURE...37...PREVIOUS RECORD 34 IN 2006. /THIS MEANS THAT NO DAYS DURING DEC HAD A HIGH TEMP. BELOW 37/
Buffalo NY:
...RECORD LOW DECEMBER SNOWFALL SET AT BUFFALO NY... ...RECORD WARM DECEMBER AVERAGE TEMPERATURE SET AT BUFFALO NY... THE MONTHLY TOTAL SNOW FOR DECEMBER WAS 1.0 INCH. THIS SETS A NEW RECORD FOR THE LEAST SNOWY DECEMBER...BREAKING THE PREVIOUS RECORD OF 1.1 INCHES SET IN 1891 AND 1889. THE AVERAGE TEMPERATURE FOR THE MONTH WAS 42.1 DEGREES. THIS SETS A NEW RECORD FOR THE WARMEST DECEMBER...SHATTERING THE OLD RECORD OF 37.6 DEGREES SET IN 1923.
Note the record exceeded the previous one by 4.5o F! Other places exceeded their old records by as much as 7-8oF. Buffalo also had its latest first day of measurable snow in the historical record.
New York City:
Washington DC:
ATREAGANNATIONAL AIRPORT...WASHINGTON DC...THE AVERAGE MONTHLY TEMPERATURE OF 51.2 DEGREES FOR DECEMBER 2015 WAS THE WARMEST DECEMBER ON RECORD. IT BREAKS THE PREVIOUS AVERAGE MONTHLY DECEMBER RECORD OF 45.6 DEGREES SET IN DECEMBERS OF 1889 AND 1984.Only 1 day with a 32oF minimum. Not even a snow flurry. 6 consecutive days the temperature didn’t fall below 50oF. A record high minimum temperature for any December.
No snowballs were thrown in the US Senate chamber, needless to say. Republicans were remarkably silent about the unusual weather.
The average temperature at Cape Hatteras NC was 62.8oF, which is normal for December in Orlando FL (which also had a record warm December).
The furthest westward extent I could find for “warmest December in the historical record” was Waterloo, IA (northeast of Des Moines), though many stations in the northern and central Mississippi Valley were in top 10 territory. To the south, most stations from TX and AR eastward to the Atlantic and Gulf coasts were either warmest or at least in the top 10.
Now, as statisticians know, one event does not a conclusive statement make, about climate or anything else, for that matter. So what about the larger context?