We've been somewhat spoiled with the warmer-than-usual weather for quite a bit of January. Now that the weekend's becoming drastically colder, we might not realize it's more of what temperatures should be at this time of year. Environment and Climate Change Canada Meteorologist Terri Lang explains what's happening and what we can expect moving into February. 

"For the better part of the month, we had that fog and the low cloud," says Lang. "So, what's happened is the jet stream is finally slipping further to the south. It's putting us on the cold side of the jet stream. That's allowing the air from the Arctic and it is making its way all the way from Siberia, which is not uncommon because that's often the source region for our cold air."

Lang explains this jet stream is sinking over much of Western Canada and will hang around once it settles. She notes it's hard to move once it positions itself like that. Lang says the jet stream marks the cold air above it from the warm air south of it. 

"So, people should be prepared to be in the cold weather, probably, for the next week," continues Lang. "The jet stream is sort of the delineator between the cold air and the warm air. We actually had sort of a split jet with one way to the north that was taking storms across the Arctic, and one way to the South that was causing all the issues that we saw in California, bringing all those storms on shore there. In the middle, was sort of this nothingness. There were no weather systems moving through, and there was no stirring of the lower atmosphere. So, we kind of got caught in this low cloud and fog."

She says this kept a blanket over most of the prairies for much of January. 

"Also, we saw a lot of that rime icing that started to cause some issues because it was building up on power lines. It also made for fun driving conditions, and trying to scrape your car in the morning," notes Lang. "Once the jet stream started getting a little bit more active, then we saw the one to the north is starting to plunge down, and that's why we're getting into the cold."

Lang explains the jet stream divides cold air to the north and warm to the south, and is the line of travel that many weather systems follow. 

"That's why the one system, that we saw moving through yesterday, zipping along that jet stream, as it was plunging the south," says Lang. "So, it started out mild and then -- boom -- into that cold air."

Statistics of how the month fared so far, including dates up to January 24, saw Portage standing at 5.7 degrees above average so far, making this edition of the month the seventh warmest January in 111 years. She says February of last year was -1.6 below average. 

"This February is probably going to be in the top 10 for the warmest, considering January is sitting at seventh warmest," adds Lang. 

Lang says to be prepared for cold weather when traveling, noting it can be easy to get away from preparations in case something goes wrong in much colder conditions after we've enjoyed such warmer weather. 

"February will often be a very, very cold month," says Lang. "We do expect those wind chill values to get below that minus-30 mark, and that's starting to get into that dangerous range. Always remember, when travelling out on the highways, to be prepared for the weather conditions, having an emergency kit in your car, and be dressed appropriately."