O dreamy days that linger
With trace of summer yet!
So soft, so mild, so mellow...
O peaceful days and golden!
Ye call back summer flowers...
--Alice Lord, "Indian Summer's Aftermath"
On account the combination of a super El Niño and a predominantly positive Arctic Oscillation, a large part of North America and Europe experienced an exceptionally warm December. In parts of North America, including the New York City area, the magnitude of warmth was historic when compared with past records. Its 50.8°F/10.4°C average temperature was, by far the highest on record for December and would have edged 1999 for the 9th warmest November on record.
Monthly temperature data for select cities:
Summary data for New York City:
In New York City, numerous daily record high minimum and maximum temperature records were set or tied.
Record High Maximum Temperatures:
December 13: 67°F/19.4°C (broke record of 64°F/17.8°C, 1923)
December 14: 67°F/19.4°C (tied record of 67°F/19.4°C, 1881)
December 15: 68°F/20.0°C (broke record of 67°F/19.4°C, 2008)
December 24: 72°F/22.2°C (broke record of 63°/17.2°C, 1996)
December 25: 66°F/18.9°C (broke record of 64°/17.8°C, 1982)
Record High Minimum Temperatures:
December 11: 50°F/10.0°C (broke record of 48°F/8.9°C, 1971)
December 12: 55°F/12.8°C (broke record of 53°F/11.7°C, 1899)
December 13: 55°F/12.8°C (broke record of 51°F/10.6°C, 1991)
December 14: 53°F/11.7°C (tied record of 53°F/11.7°C, 2001)
December 15: 53°F/11.7°C (broke record of 48°F/8.9°C, 2001)
December 17: 50°F/10.0°C (broke record of 48°F/8.9°C, 1984)
December 24: 63°F/17.2°C (broke record of 50°F/10.0°C, 1931)
December 25: 57°F/13.9°C (broke record of 50°F/10.0°C, 1979)
The low temperature of December 24 tied the previous record high temperature for the date. It set a new monthly record for the warmest minimum temperature recorded in December. It is the highest minimum temperature registered in the November 10-March 27 timeframe.
In addition, for the first time on record, December had no days on which the temperature fell to 32°F (0.0°C) or below. The previous fewest days on record for December was 6 days. That record was set in 1984 and tied in 2006. The 11 days on which the low temperature was 50°F/10.0°C or above tied the record for November.
December 2015 was 6.7°F/3.7°C warmer than the previous warmest December on record. As of the end of December, no other month has such a large difference between its most extreme cold or warm value and its second most extreme respective value.
Finally, December 2015 was warmer than Octobers 1876, 1888, 1889, and 1925.
December 2015 vs. October 1889:
On account of this historic warmth, flowers bloomed, frogs remained active, turtles basked in the often warm sun, and bees and other pollinating insects flew from flower to flower. Numerous images from this extraordinary December follow below and on subsequent pages devoted to the historic warmth of December 2015.