Rapid City Has Least Predictable Weather in America

Rapid City—Land of Climatological Adventure!

So says Nate Silver, who now that the election is over has time to crunch meteorological data to determine what parts of the United States have the most unpredictable weather. Silver and FiveThirtyEight.com colleague Reuben Fischer-Baum calculate how much temperature, precipitation, and severe weather vary from climatological averages for major cities in each of the 120 National Weather Service forecast office areas. Silver and Fischer-Baum find the greatest daily deviations (from 2011 to 2013) from averages in Rapid City:

The ICAO code for Rapid City Regional Airport is KRAP. That’s also a good description of Rapid City’s weather. Its temperature might be 30 degrees in January — or just as easily -12. It’s snowy and windy and prone to big, unexpected winter storms. And it has a thunderstorm on almost 25 percent of days from July through September, more than the national average [Nate Silver and Reuben Fischer-Baum, "Which City Has The Most Unpredictable Weather?" FiveThirtyEight.com, 2014.12.04].

Sioux Falls comes in fourth for weather unpredictability; Aberdeen comes in eighth. The places with the most boring weather include Las Vegas, Phoenix, Los Angeles, and, most boring of all, Honolulu. (Yeah, but one eruption, one tsunami, and Honolulu's all gone!)

Here are the top fifteen (there's a six-way tie for tenth) and the bottom ten... which "top" and "bottom" should probably be reworded for those of you preferring boring weather:

Silver and Fischer-Baum cite landlockedness as the primary factor in weather unpredictability. Big lakes and oceans moderate temperatures and make stormy weather more predictable.

But hey! Who wants the same old weather day after day after day? Sunshine and 70 degrees one day, snow flurries the next—that's living!