South Bend Has 12th Most Unpredictable Weather Among Major US Cities

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Anyone that has spent an extended amount of time in Michiana would agree that the weather around here is unpredictable. It could be 60 degrees one day and in the teens with a foot of snow the next.

That’s just life in the Midwest where frontal boundaries collide with unusual force and severity.

South Bend is unusually unpredictable in a region known for its unpredictability. Much of this is due to the fact that the city is situated roughly 30 miles from Lake Michigan with a predominately westerly wind pattern.

Lake effect snow is far less predictable than cold fronts in the amount of snow that will be dumped and in the location. Chicago, which is only 90 miles away, sees far less snow during the winter thanks to the wind direction that favors lake effect snow on the eastern shore of Lake Michigan.

But like the rest of the Midwest, daily temperature fluctuations are common as well.

An analysis from Nate Silver and Reuben Fischer-Baum of FiveThirtyEight.com compiled National Weather Service (NWS) data across 120 cities in all 50 states to come up with a list of cities with the most unpredictable weather for day-to-day forecasting. We narrowed the list down even further to the top 20 most unpredictable with populations of at least 100,000 people.

“Take the case of Phoenix, for example. The chart below compares high temperatures in Phoenix on each day from 2011 through 2013 against the 20-year average for the week in question. On a typical day in Phoenix, the high temperature deviated from the long-term average by only 5 to 6 degrees. You could plan a wedding or golf tournament in Phoenix years in advance and be reasonably confident of what the temperature would be,” the authors write.

“This wouldn’t be true for Denver. Over the past three years, climatology has missed the high temperature there by 9 to 10 degrees on average. And misses of 20 degrees or more, which almost never happen in Phoenix, have occurred, on average, once every other week in Denver,” they add.

They caution that this is not to suggest that the weather is either good or bad based on their rankings, or that cities with consistent seasonal volatility would not qualify as unpredictable.

The authors measured predictability across three different major categories: temperature, precipitation and severe weather. They then controlled for outliers and standardized the data to fit neatly on a common scale.

Their findings?

Each of the top 10 most unpredictable cities are in states that would traditionally be defined as the Midwest with the exception of Montana. However, most of them are in the less populated Great Plains region rather than the more populated Great Lakes region.

South Bend is the 12th most unpredictable city in the country with a population over 100,000 within their 120 city sample. South Bend scores “above average” in unpredictability for temperature, precipitation and severe weather.

South Bend’s temperature score actually approaches the authors’ self-defined “very high unpredictability” level, while its lowest score is for severe weather.

Nearby major cities like Chicago and Detroit fall into or near the “average” range of unpredictability — again, due largely to wind patterns and geographic relation to the Great Lakes that determine lake effect snow areas.

The most predictable cities are entirely predictable.

Number one? Honolulu, Hawaii, followed by San Diego, Los Angeles and Phoenix.

Below we have a list of the top 20 cities with populations of 100,000 or more ranked by climate unpredictability:

  1. Sioux Falls, South Dakota
  2. Fargo, North Dakota
  3. Omaha, Nebraska
  4. Springfield, Illinois
  5. Tulsa, Oklahoma
  6. Billings, Montana
  7. Topeka, Kansas
  8. Davenport, Iowa
  9. Witchita, Kansas
  10. Des Moines, Iowa
  11. Kansas City, Missouri
  12. South Bend, Indiana
  13. Oklahoma City, Oklahoma
  14. Minneapolis, Minnesota
  15. Lexington, Kentucky
  16. Cincinnati, Ohio
  17. Indianapolis, Indiana
  18. St. Louis, Missouri
  19. Green Bay, Wisconsin
  20. Amarillo, Texas

Certainly there is room for debate about some of the variables used but no matter what way you cut it, the findings confirm what we already know: the weather in Michiana can flip on a dime.

For more details on the methodology and a full list of city unpredictability index, visit FiveThirtyEight.com.

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