Frigid cold for the next 36 hours in Montreal

Winter has been relatively tame to date in Montreal, with mainly mild weather and very little snow. That will make the next 48 hours seem even colder for most, as frigid arctic air settles over the province. Morning lows early Tuesday will be in the middle minus 20s, with windchill values approaching -40C in many locations.

Extreme cold warning for southern Quebec for Monday night and Tuesday. Expect temperatures in the -20s with windchill values approaching -40C. Exposed skin can freeze in minutes. Make sure your pets are indoors.

Arctic air will invade southern Quebec on Monday behind weak low pressure that brought Montreal a few centimetres of mixed precipitation on Sunday. The temperature briefly warmed above freezing late Sunday afternoon, but has since dropped considerably on gusty northwest winds. Trudeau Airport early Monday morning was -12C (10F), and I don't expect any movement on the mercury today, perhaps even dropping a few degrees by sunset.

Tonight, the coldest airmass of the season will settle over most of Quebec, with extreme cold warnings in effect across the province. The forecast low for metro Montreal is -26C (-15F), which if reached, would make it the coldest night in Montreal since January 14, 2018. To date the coldest low was -21C (-6F) on January 3. The coldest day last winter was -23C (-9.5F) on January 31.

Accompanying the cold will be a brisk northwest wind between 20 and 40km/h, producing windchill values close to -40C for many parts of the province. The temperature will slowly recover on Tuesday under partial sunshine, reaching -19C (-2F) by late in the day.

Much milder air arrives by Wednesday, with daytime highs reaching -5C (23F), along with just a few flurries. Colder air returns by the end of the week, but not as frigid as the next day or so. At this time, there are no major storms on the horizon. However, if your travels take you into southern Ontario or western New York, expect areas of snow squalls, with very heavy snow and near-blizzard conditions. This is especially true south of Watertown, New York, along Highway 401 near Kingston and southeast of Georgian Bay.