Looking at 16 cities – mainly in the north -- since 1960, the number of white Christmases per decade declined from 78 during the 1960s to 39 in the 1990s. People in Chicago, for example, saw the number of white Christmases – defined as at least one inch of snow on the ground – drop from seven in the 1960s to two during the 1990s. In New York, the number declined from five in the 1960s to one this past decade, and Detroit had just three white Christmases in the 1990s vs. nine in the 1960s.
But in several cities, the number of white Christmases has been fairly constant. Looking at the 1960s, ’70s, ’80s and’90s, Tahoe City, Calif., had eight, seven, eight and nine white Christmases, respectively. Salt Lake City’s number of white Christmases per decade were seven, seven, eight and eight. Minneapolis/St. Paul had eight white Christmases in the 1960s, seven in each of the following two decades and eight in the 1990s.
In Tennessee, Memphis, Nashville and Knoxville/Oak Ridge had several white Christmases in the 1960s – three in Memphis, two in Nashville and four in Knoxville/Oak Ridge -- but none in the 1980s or 1990s.
As defined for this survey, Atlanta hasn’t had a white Christmas since the record-keeping process began in 1896.
Following are metropolitan areas used in the study followed in parentheses by the number of white Christmases for each of the last four decades:
Seattle (2, 0, 0, 0)
Tahoe City, Calif. (8, 7, 8, 9)
Salt Lake City, Utah (7, 7, 8, 8)
Denver (4, 4, 7, 2)
Minneapolis/St. Paul (8, 7, 7, 8)
Kansas City, Mo. (4, 0, 6, 2)
Chicago (7, 5, 4, 2)
Detroit (9, 7, 5, 3)
Cincinnati (3, 0, 2, 2)
Boston (8, 5, 5, 2)
New York City (5, 1, 1, 1)
Washington, D.C. (4, 0, 0, 0)
Memphis (3, 0, 0, 0)
Nashville (2, 0, 0, 0)
Knoxville/Oak Ridge (4, 1, 0, 0)
Atlanta (0, 0, 0, 0)
The snowfall analysis was performed by Dale Kaiser, a meteorologist with the Carbon Dioxide Information Analysis Center at the Department of Energy’s Oak Ridge National Laboratory, and Kevin Birdwell, a meteorologist in the lab’s Computational Science and Engineering Division.
For many cities, the weather described by the data is actually what was recorded at a suburban station several miles away, Bob Cushman, director of the Carbon Dioxide Information Analysis Center, noted. For example, the weather for Washington, D.C., was actually recorded at Glen Dale, Md.
Cushman advised against reading too much into the analysis, saying, "After all, we’re only looking at one aspect of weather on one specific day each year. Whether there is snow on the ground on Dec. 25 may or may not relate to the larger issue of whether the U.S., or any region in the country, is experiencing an overall warming trend."
The Carbon Dioxide Information Analysis Center (http://cdiac.ornl.gov/), which includes the World Data Center for Atmospheric Trace Gases, is the primary global change data and information analysis center of the Department of Energy. The center responds to requests for data and information from users from all over the world.
Oak Ridge National Laboratory is a Department of Energy multiprogram research facility managed by UT-Battelle.
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