- This year will have a strong El Nino for Christmas.
- El Niño means warmer-than-average temperatures in the low 48s, which will affect snow chances.
- However, the chance of a white Christmas in all regions during a strong El Niño is not low.
El Niño can produce more or less snow than an average winter depending on many factors. What does this mean for your chances of a white Christmas?
A strong El Niño is in effect this year and there have been eight strong El Niños since 1950. Not all strong El Niños are as the most recent one proves, so we examined data from those eight Christmases for clues. What can we expect this year?
What counts as a “white Christmas”? There should be at least an inch of snow on the ground on Christmas morning. A real holiday doesn’t have to snow. Not even a trace of snow counts.
The graph below shows the historical probability of a white Christmas based on data from 1991-2020. The odds of a white Christmas are over 50% for much of the Mountain West and North.
There is an overall temperature and rainfall pattern that emerges in December. 1957, 1965, 1972, 1982, 1991, 1997, 2009 and 2015 were the eight years of strongest El Niño. Combining those years and comparing them to the current 30-year average (1991-2020), a distinct December temperature pattern emerges and is shown in the graph below.
The temperature pattern for strong El Niño Decembers includes warmer-than-average conditions for the Northern Plains, Midwest, and the South and Northeast. Much of the West experienced cooler than average temperatures.
December rainfall in strong El Niño years also has some interesting features. Precipitation is above average in most of the South, as well as the central Mississippi Valley and the southern Great Lakes. There are signals of higher than average rainfall in the south-west and north-west regions.
Interestingly, Northern California sees less than average precipitation for December. The overall theme of those eight years was close to average for the rest of the Lower 48.
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Strong El Niño years reduce the chances of a white Christmas in the Northeast. Major cities in the Northeast rarely see snow on the ground on Christmas morning, which is true of strong El Niño years, with most only experiencing a white Christmas in 2009.
Much of the interior Northeast and northern New England, however, measured less than average snow for Christmas during those eight strong El Niño years. The lack of snow in parts of the Northern Tier is part of the warmer temperatures that can accompany El Niño.
Syracuse, New York, for example, has a 58% chance of an overall white Christmas, but only reported one inch of snow in 1991 and two inches in 2009, a 25% chance in strong El Niño years. Pittsburgh has only seen a white Christmas once when a strong El Niño occurred, less than its usual 32% chance.
All of the strong El Niño years saw bare land in the Midwest. The absence of a white Christmas is notable in Cleveland and Detroit, where about 40% of Christmases have at least an inch of snow on the ground, but strong El Niño years do not meet the White Christmas criteria. Neither Indianapolis nor St. Louis had a white Christmas in those eight years.
Minneapolis reported a white Christmas one in three out of eight years, which is less than their overall chance of 74%. However, Des Moines, Iowa saw its sixth white Christmas in eight years, well above the 30-year average of their 43% chance.
All eight years in Duluth, Minnesota were classified as white Christmases, close to their average of 92%. Chicago had an inch or two in four over eight years, not far from their average 41% chance.
The West is the winner for a white Christmas in strong El Niño years. Western locations that typically enjoy a white Christmas are more likely during a strong El Niño. This is due to the generally more active jet stream across the West during El Nino years.
Tahoe City, Flagstaff and Salt Lake City all have a 20% higher chance of seeing a white Christmas in a strong El Niño year. However, as shown below, the amount of snow on the ground varies greatly. To the east, Billings, Montana reported a white Christmas in four of eight years, well above its 30-year average of 42%.
As expected, Anchorage and Fairbanks, Alaska, had eight years of white Christmases, with two inches to 23 inches of snow on the ground in Anchorage and three to 39 inches in Fairbanks.
Linda Lam A leading meteorologist at weather.com. Growing up in Massachusetts, he developed a fascination with winter storms and tornadoes that led him to pursue a career in meteorology.
The Meteorological Institute’s primary journalistic mission is to report on weather news, the environment and the importance of science in our lives. This story does not necessarily represent the position of our parent company, IBM.