December 2018 Temperature Outlook: Warmer Trend in the East With Colder Than Average Conditions in Parts of the West

Linda Lam
Published: December 1, 2018

Temperatures in December may look a bit different than those experienced in much of the U.S. in November, according to the latest outlook from The Weather Company, an IBM Business.

Many areas in the eastern and central U.S. experienced record cold in November, but there are signs that a warmer pattern will emerge across much of the contiguous U.S. in mid-December. That pattern change combined with the emerging El Niño will bring a warming trend to much of the contiguous U.S that may last into late December.

(MORE: December Temperature Changes)

December 2018 temperature outlook from The Weather Company, an IBM Business.

Overall temperatures are expected to be near-to-slightly-above average from the Plains to the East Coast.

Above-average temperatures are expected from the Northwest into the northern Great Lakes, while portions of the Southwest, Great Basin and Rockies may experience near-to-below-average conditions.

"Given the strong medium-range model signals for northern U.S. warmth by the second week of December, which match historical El Niño December aggregates, along with sub-seasonal signals, we've made significant warmer changes to the December forecast," notes Dr. Todd Crawford, chief meteorologist with The Weather Company.

(MAPS: 10-Day Forecast)

Crawford points out that this warmer change to December "does not change our expectations for a much colder late-winter period, as November blocking, the current El Niño event and expected North Atlantic blocking associated with the solar minimum add up to heavily skewed odds towards colder/stormier period in the eastern U.S."

December through February temperature outlook from The Weather Company, an IBM Business.

Due to these factors, the outlook for December through February indicates that the eastern half of the U.S. will likely see near or slightly-below average-temperatures overall while warmer-than-average conditions will persist in the Northwest.

Average Temperatures in December

A quick, but important note: This December temperature outlook looks at how the overall temperatures for a given month compared to historical averages and isn't an indication of exactly what temperatures you will experience on any given day in December. Cold snaps and warmups can cause individual temperatures to drop or rise, regardless of these overall projections for the month. 


Average Highs in December

Still, based on December's projections of near-average or slightly-below average temperatures in the central and eastern U.S., people there should expect mild or even warm conditions in the South, particularly in Florida. Much-above average projections for December overall in the Northwest would also lead to fairly mild temperatures.

(MAPS: Average High and Low Temperatures)

Cooler-than-average projections in the West could result in quite cold conditions in the Rockies and Great Basin. Given low average temperatures in these areas in December, cooler-than-average projections could translate to lows in the single digits above or below zero.


Average Lows in December

Even near-average or slightly-warmer-than-average lows in December are cold enough for snow from the northern Plains into the Midwest and Northeast.


The Weather Company’s primary journalistic mission is to report on breaking weather news, the environment and the importance of science to our lives. This story does not necessarily represent the position of our parent company, IBM.