cold front sept 2014
Cold is about to sweep into the northern U.S. Plains from Canada and drop temperatures to winter-like levels.

Readings in Calgary were forecast to drop to 27 Fahrenheit (minus 3 Celsius) later this week and snow was flying there yesterday, according to Environment Canada.

That will be a welcome change for energy traders after a mild summer, although it's just a glimpse of what may come.

While the temperatures will drop, they won't be falling too far where it counts.

Chicago, for instance, will end this week with highs in the 60s and lows in the 50s, according to the U.S. National Weather Service. New York will reach into the 80s during the day and 60s at night.

The big cities of Canada also won't see much of the cold. Overnight temperatures in Toronto and Montreal will drop into the 40s by the end of the week.

In New England, conditions like that are called "good sleeping weather."

For the cold to matter, it has to have a bite and it has to be where a lot of people live. A frigid blast that stretches from Chicago to Texas or across the U.S. Northeast would cause utilities to really burn some gas.

That's why snow in the Rocky Mountains in July and crispy temperatures in the Sierra Nevada don't register much on the trading floors.

From July 1 through yesterday, the temperature dropped into the 20s at least 23 times across the contiguous U.S., according to the Weather Prediction Center in College Park, Maryland. Stanley, Idaho, posted the lowest temperature in the U.S. six times followed by Bodie State Park, California, which had the lowest mark four times.

Stanley had an estimated population of 69 in 2013, according to the U.S. Census Bureau. Bodie is a ghost town, which is why it is state park, north of Mono Lake and near the border of Nevada up in the mountains.