It's warmer than normal in many parts of the North — and it's going to stay that way for awhile

During the first week of January, Charles Auger was walking in downtown Yellowknife wearing a baseball cap. 

"It's been so warm," he said. "Haven't seen it like [this] in years." 

The average low in the city this time of year is –30 C, according to Environment and Climate Change Canada. But as of Thursday, the thermostat hadn't dropped below –17 C for a week. 

Terri Lang, a meteorologist with the weather agency, said Yukon, the N.W.T. and western Arctic are all experiencing above-average temperatures because of how a jet stream is positioned over Western Canada — and it's projected to stay that way for the rest of the month.

The jet stream

In Canada, the polar jet stream is responsible for many of our weather patterns. It is a narrow band of fast-moving air in the upper atmosphere that can help direct our weather systems. 

It also divides warm and cold air — cold air remains to the north and warm air to the south. 

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As Milli Vanilli would say, "you gotta blame it on something." And in Canada, the cause behind those major weather events is often the jet stream, a fast-moving ribbon of air that circles the planet separating hot and cold air masses. Meteorologist Christy Climenhaga has more.

Though it generally travels from west to east, the jet stream can weaken and become kinked and wavy. Those waves can lead to colder- or warmer-than-normal weather, by allowing polar air to spill southward or warm air to push north. 

Lang said the jet stream is going up the coast of B.C., over the Yukon, and down through Nunavut. Because Yukon, the N.W.T., and Western Nunavut are all currently south of the jet stream — the weather is warmer than normal, she said. 

Meanwhile, a big polar vortex with really cold temperatures is rooted over the eastern Arctic — where the jet stream dips south again. 

What does this have to do with climate change? 

Warmer temperatures are part of the changing climate. In the N.W.T., for example, the mean annual temperature has gone up between 2 and 4 C since 1950. 

But Lang said you can't look at a short spell of warm weather and draw a direct link. 

"There's evidence that OK, this could be part of [climate change], but … it has to be studied over that longer term to see if that you know, is this part of a trend or is it just part of the natural variation of climate itself." 

In the short term — keep your biggest parka handy.

Lang said temperatures are expected to stay warmer-than-average in Yukon, the N.W.T. and western Nunavut for four weeks, but after that, she's not sure what the jet stream will do.

"It'll be interesting to see if it kind of holds," she said. "We still have to get through the month of February, which we know can be one of the coldest months."