How Bad Is This Winter? There’s a Way to Check That.

Is it unusually bad out there, or is it just normal-level cold?

A forlorn-looking woman stares out the window at snow.
Photo illustration by Slate. Images by Marjan_Apostolovic/iStock and meyrass/iStock.

I think I speak for most of us when I say that so far, this winter has sucked. But how much has it sucked? More than usual? Are we misremembering what winter feels like? Is there a method for measuring its suckousity?

In fact there is—meet the Accumulated Winter Season Severity Index. This index allows us to assess whether it’s the worst winter ever or nothing unusual. And since the AWSSI is cumulative and calculated on a daily basis, winter’s crescendo of agony can be tracked in real time. The fifth snowstorm really is worse than the first, and that’s reflected here.

Here’s how it works: The AWSSI takes into account temperature averages and extremes, snowfall totals and daily snow depth, even the yearly onset and departure of winter weather. Basically any part of the winter scenario that bothers folks is awarded points.

Astronomically winter began Dec. 21, but AWSSI’s winter begins on Dec. 1 unless it’s triggered earlier by the first day with the maximum temperature failing to reach 32 degrees or .1 inches of snowfall. This also means that there’s no AWSSI for Miami or San Diego.

The scale is designed to give more weight to unusual winter events. A maximum temperature of 25 to 32 degrees adds a point to the score. When you peak below minus 20 degrees, 15 points gets tacked on. The same goes for snow. The first few inches count a point apiece. Get 30 inches, and you rack up 45 points.

The actual AWSSI number is supposed to be objective, though even the index’s authors admit, “the thresholds are admittedly somewhat arbitrary.”

With climatology we can see any location’s average score and easily compare. Though parts of interior Alaska score in the 3,500 to 5,000 range, the contiguous 48 states top out at less than 3,000. The northern plains and northern Great Lakes lead the way, though the highest average score lives atop Mount Washington, New Hampshire.

The AWSSI says average winter sucks about the same in Kansas City, Missouri; Des Moines, Iowa; Milwaukee; Detroit; and Hartford, Connecticut. Of course that’s in an average season, which this season is decidedly not! This is a winter with snow in Florida.

To compare years more accurately the AWSSI for each location is divided into quintiles. The lowest 20 percent is considered mild, then moderate, average, severe, and extreme. This season there’s a lot of extreme on the map stretching from Richmond, Virginia, to Bangor, Maine.

A map of the U.S. with color-coded AWSSI rankings of extreme, severe, average, moderate, and mild.
Midwestern Regional Climate Center

Most of the easier than normal winter weather has taken place west of the Rockies. Salt Lake City is close to record-low territory with a current reading of 97. This time of year, it’s usually in the mid-200s.

Oklahoma City, on average much gentler than Salt Lake City, clocks in at 93. Statistically there’s not enough difference to matter. This season OKC and SLC are comparable so far, according to AWSSI.

The AWSSI is updated every day, but that doesn’t mean the number will necessarily change. At last check the reading from Central Park in New York City is 180, well up in the extreme category. If, however, the rest of the winter were mild and snow-free, New York City would end up average.

Of course, that probably won’t happen. The numbers will continue to rise and each additional wintry blast will take its toll on you as it adds to the AWSSI.