In Portage la Prairie, people are always curious about what kind of winter is coming, and for good reason. Farmers, drivers, and families want to know whether it will be colder than usual, or if the warmer fall weather will continue. This year, forecasts point to a weak La Niña pattern, and that means the season could turn out milder than many might expect, explains William Merryfield, research scientist at the Canadian Centre for Climate Modelling and Analysis with Environment and Climate Change Canada explains. Timing of La Niña effects Merryfield notes that La Niña generally brings colder-than-usual conditions from the British Columbia coast through to central Canada, including Manitoba. However, he says those effects do not usually settle in until around Christmas and tend to peak through the early winter months, sometimes lingering into spring. “So right now, we’re still a little bit early to be feeling the effects of the La Niña, particularly a fairly weak one, as is being predicted for this winter,” says Merryfield. He describes how the current outlook reflects Canada’s weather which has accelerated since the midpoint of the 1991 to 2020 climate reference period. “The current forecast is really not reflecting the influence of La Niña, and what it’s reflecting instead is the pronounced warming trend in Canada,” notes Merryfield. Variability and past winters Merryfield continues by pointing out that although La Niña and El Niño events help set the stage for seasonal outcomes, other factors can override them. “The winter of 2011 to 2012 was a La Niña winter, but actually was very warm throughout much of central and southern Canada,” explains Merryfield. “But other La Niña winters have been quite cold, and certainly some El Niño winters have been quite warm, like 2015 to 2016, for example.” He says the impact on precipitation is less pronounced than on temperature, with western Canada more likely to see above-average snowfall, while our area historically shows little consistent connection. Unusual recent patterns Merryfield adds that the frequency of La Niña events in recent years has been striking. “Lately we’ve been stuck in a bit of a broken record with La Niñas occurring, if one indeed does materialize this winter, something like four of the last five years, or even five of the last six years, and that’s quite unusual,” says Merryfield. He says scientists are actively studying whether the repeated patterns could be related to climate change. Related stories: Mild Winter Forecast For Manitoba The Old Farmer’s Almanac Winter 2025 Forecast Outlook for Portage Looking ahead, Merryfield says the weak La Niña will be competing with the ongoing warming trend. “The forecast for the winter is slightly favoring above-normal temperatures, but not with any strong indication,” says Merryfield. “It could be near normal or perhaps even the La Niña influence will cause it to be a bit below normal, but we’re not expecting a strong cooling influence by historical standards.” He reminds people that nature can still deliver surprises. “The latest first measurable snowfall, which was getting into late November in Winnipeg, occurred in 2016,” continues Merryfield. “That was actually going into another weak La Niña winter. So November that year was exceptionally warm, but as you get further into the winter, the La Niña influence was indeed felt.”