UNITED STATES

Perhaps you’ve heard the line: “If you don’t like the weather in Chicago, wait five minutes.” Or you’ve heard it applied to a city nearer to you: Denver or San Francisco or Atlanta or Boston. But where in the country is the weather truly the most unpredictable? (FiveThirtyEight)

How do scientists measure weather?

Teachers, scroll down for a quick list of key resources in our Teachers Toolkit, including today’s MapMaker Interactive map.

Discussion Ideas

• How does the FiveThirtyEight article define “unpredictable weather”?
  • They compared weather to climate. Weather describes the state of the atmosphere over short periods of time—changing from hour to hour, day to day, month to month and year to year. Climate describes long-term weather patterns, usually at least 20 to 30 years.
  • In this case, analysts compared daily weather patterns to 20-year climate averages. The most meteorologically unpredictable areas are where the weather (the daily forecast) deviated the most from climate (long-term averages).

• What weather patterns were tracked?
  • The 10 weather patterns analyzed by researchers fall into three major categories: temperature, precipitation, and severe or extreme weather.
    • temperature
      • high temperatures
      • low temperatures
      • mean, or average, daily temperatures
    • precipitation
      • simple presence (1) or absence (0) of any precipitation at all
      • rainfall in inches
      • snowfall in inches
    • severe weather
      • simple presence (1) or absence (0) of any severe weather event, such as a tornado or hurricane
      • wind speed
      • humidity
      • cloud cover

• Take a look at today’s MapMaker Interactive map. Where is the most unpredictable weather in the U.S.?
  • The Upper Midwest has the most unpredictable weather in the country, with Rapid City, South Dakota; Great Falls, Montana; and Houghton, Michigan, taking the top spots.
  • “[T]he map of areas most prone to unpredictable, severe weather generally follows Tornado Alley, with cities in the line of states from South Dakota through Oklahoma and northern Texas ranking toward the top of the list.”
    • Compare this map of unpredictable weather with this map of Tornado Alley.

• Why do you think the Upper Midwest has such unpredictable weather? Consider the weather patterns that were evaluated.
  • temperature. Unlike the West and Gulf coasts, the Upper Midwest experiences seasonal variations—winters may have blizzards, or they may have no snowfall at all; summers may be triple-digit hot or mid-temperature mild.
  • precipitation. Unlike the consistently rainy Northwest and consistently dry Southwest, the Upper Midwest experiences variable and varied precipitation: snowfall, rain, drought.
  • severe weather events. “Tornado Alley” is also prone to floods, drought, thunderstorms, hail, and other extreme weather.

TEACHERS TOOLKIT

FiveThirtyEight: Which City Has The Most Unpredictable Weather?

Nat Geo: What cities have the most unpredictable weather in the U.S.? map