At a Glance

Arctic cold this week may leave some wondering, "If Earth is warming, why is winter still so cold?"The answer lies between the difference in climate and weather.

With a this week, it can be easy to forget that .

You might be wondering, "If everything is warming, why is winter still so cold?" Part of that answer is within the difference between weather and climate.

One of the better ways to explain comes from the University Corporation for Atmospheric Research. Picture walking a dog. As you walk along, the dog's path will vary much more than yours. It'll swerve to the left or right, while you'll travel in a much more direct path. However, in the end, .

(MORE: Midwest Cities Will be Colder Than Antarctica, Alaska)

Climate — the person walking the dog — is how weather behaves over a long period of time, normally an average of weather data over the course of 30 years or so. The weather — the dog — has much more variation because it refers to atmospheric conditions on a much shorter timeframe.

Even as a rush of arctic air is forcing its way into the Midwest with wind chill predictions reaching minus 65 in some of the coldest spots, the world as a whole is warmer than average.

Take for example Tuesday, Jan. 29, 2019:

The high in Fargo, North Dakota, is predicted to reach between 15 to 20 degrees below zero — well below the average high of 20 degrees — the rest of the world is roughly , according to the University of Maine's Climate Reanalyzer.

(Climate Change Institute, University of Maine)

But just because Earth continues to warm doesn't mean we're going to see winter fade away. In the 1950s, the U.S. saw just about the same number amount of record high temperatures as they did record low temperatures. In the 2000s, , according to a study published in American Geophysical Union.

In short, record low temperatures will still pop up every now and again, but much less often.

The roots of this dangerously cold snap in the Midwest lie in an episode of sudden stratospheric warming — a rapid increase in temperature in the typically-frigid air above the North Pole that took place at the end of December — which caused the polar vortex to split.

The polar vortex is a large zone of low pressure and cold air that always exists near both of the Earth's poles in the stratosphere, a few miles above ground level. The vortex , the National Weather Service describes.

When the polar vortex splits, pockets of arctic air that normally reside near ground level over the North Pole are allowed to roam southward.

“Where the polar vortex goes, so goes the cold air,” Judah Cohen told the Associated Press. Cohen, who works for the New England-based firm Atmospheric Environmental Research, that the polar vortex is expected to re-consolidate around the North Pole in early February, with milder air returning to most of the central and eastern U.S. next week. However, unusually cold air is still expected to lurk near the U.S.-Canadian border. Cohen said it is possible that the lingering effects of the polar vortex split could affect North American weather for several more weeks.

“The impacts from this split, we have a ways to go. It’s not the end of the movie yet,” according to Cohen. “I think at a minimum, we’re looking at mid-February, possibly through mid-March.”

In a 2018 study in the Bulletin of the American Meteorological Society which Cohen helped author, researchers found that "over recent decades, the ," allowing it to stray from its home above the North Pole.