Here it is! Last year’s winter was quite a rollercoaster, with long periods of alternating warm and cold, as well as a lot of snow. So, what will it be this year? Currently, we’re far enough away that we can’t really be certain on anything. However, there seems to be an increasing amount of evidence of near to below normal temperatures, and near to above normal snowfall. Here, I’ll list out all of those signs.
Before we start, I would like to clarify what time range I mean by “winter.” Technically, it’s December 21 to March 19. That, however, does not really show the actual length of an Edmonton winter. Our typical first snow that doesn’t entirely melt until spring is in the first half of November. So we’ll put the start there, but for convenience round it to the beginning of November. For the end, we’ll say it occurs when the snow may still be on the ground, but the warming is noticeable and it’s starting to actually feel like spring. This would usually happen in the first half of March, and I’ll round it again to the start. So, our adjusted winter is November 1 to February 28.
So, let’s start with an easy one. La Niña. We are currently about 1 degree below average, with that value expected to drop even more. This isn’t a particularly strong La Niña, but not a very weak one. So, just with this, we can still expect a lot of both warm and cold, though cold will probably occur more often. Every La Niña is different, so we will have to look for other signs.
Next, the Pacific Ocean. Since spring, the sea surface temperatures in the northern Pacific, from the Gulf of Alaska to Japan, have been very very hot. This means the jet stream likes to be farther north, and that carries over to here. It’s partially the reason we were in one heat wave for most of September. During the last third of the month though, things started to finally cool down in the Gulf of Alaska. In the last week, very rapid cooling has begun in the entire area that was hot. This means the jet stream will want to stay lower, and heat waves will become much less likely, if this trend continues.
Another reason is what’s going on in Siberia. Lately there, it’s been cold, but more importantly snowy. Very snowy. A big mass of snow there is creating a mass of cold air, also pushing the jet stream south. This manufactures many a trough, meaning for the next month or two, big ridges will be very hard for the atmosphere to make.
Back to more global anomalies now. There is a condition that is stacked called Atmospheric Angular Momentum, or AAM. This has models that forecast it. For a while now, this has been far in the negatives, meaning the amount of west-to-east flow in the atmosphere has been very low. Models though, have been recently forecasting this to return to near normal, meaning fewer blocks will develop, and ones that do will be more easily broken up. For our geography, if there’s a block in the area, we’re very likely hot. If the AAM is positive, then few big heat or cold waves can occur, resulting in average temperatures. Out of all values, near neutral is the most likely one to have us end up will cold temperatures.
Finally, some more long-range models. Recently, we’ve gotten close enough that different ones are starting to agree a lot, and they’ve been saying what I said at the start of this post. Near to below normal temperatures, and near to above normal snowfall. This hasn’t just been for part of the winter time frame, but the whole thing.
One more thing to mention; conditions right now are actually surprisingly similar to last year, so last winter might not be too bad of an analog of this one.
So there you go, the preliminary 2025-26 winter forecast. It’s more like the winter forecast, because the non-preliminary forecast will probably just end up being the monthly outlooks.