The current El Niño is officially the strongest on record, according to Danielle Banks, meteorologist with the Weather Channel.
“The pattern is known for causing extreme weather, including droughts and floods, and impacts during hurricane season,” she says.
But as Christmastime approaches, Banks gets asked about a different kind of weather. Will El Niño affect the probability of getting snow for Christmas?
To answer the question, Banks dug into the last five big El Niño Christmases, in 1997, 1982, 1972, 1965 and 1957. Banks and other meteorologists qualify a true “white Christmas,” as having one inch or more of snow on the ground on Christmas morning.
The results are mixed, but on average, don’t get overly excited about queueing up any Bing Crosby holiday songs this Dec. 25.
In the Northeast, white Christmases were uncommon outside of Caribou, Maine, which has an average 92% chance of a white Christmas on any given year. Buffalo, N.Y.; Boston; New York City; Philadelphia; Pittsburgh; Syracuse, N.Y.; and Washington, D.C. all came up short on Dec. 25 snowfall under El Niño conditions.
In the Midwest, results were mixed. Some cities have under-delivered on white Christmases under El Niño conditions while others have been up to par. For example, Duluth, Minn., went 5 for 5 during El Niño Christmases, but it gets a white Christmas 97% of the time, anyway. Des Moines can expect a white Christmas 49% of the time but came through 80% of the time during El Niño years. Detroit, on the other hand, saw only trace amounts of snow during the past five El Niño years, despite having a 46% average for a white Christmas.
One factor against snowy Christmases during El Niño is that with the exception of 1972, Decembers during the last five El Niños have been warmer than average. For December 2015, NOAA is predicting warmer-than-average weather for the upper half of the United States. In fact, probabilities for above-normal temperatures exceed 70% through most of the Midwest, Great Lakes and Northeast regions.
But, as editorial meteorologist Jonathan Erdman quips, past performance doesn’t guarantee future returns.
“Day-to-day and week-to-week variability in the weather can still deliver a potent snowstorm in a location where a season-long El Niño would work against that,” he says. “Think of El Niño, then, as just one factor loading the dice for or against a white Christmas.”