Winter weather travel advisory in effect for Montreal

Environment Canada has issued a winter weather travel advisory for the St. Lawrence Valley, including metro Montreal for 10 to 15cm of snow Monday night. The snow will make for very poor travel conditions, with snow covered roads and lowered visibility. Conditions will improve during the daylight hours on Tuesday. Christmas Day is forecast to be sunny and cold. (Transport Quebec)

Widespread winter weather advisories have been issued for portions of Ontario and southern Quebec. Those weather warnings include the St. Lawrence Valley and metro Montreal. An Alberta Clipper low pressure system is expected to cross the Great Lakes and travel south of Montreal on Monday night. A swath of steady snow will spread southeast across eastern Ontario on Monday, and reach Montreal after 8pm. The snow will be moderate at times, persisting into Tuesday morning.

We can expect a decent 10 to 15cm of snow from late Monday evening into the Tuesday morning commute in Montreal, with 5 to 10cm expected elsewhere across southern Quebec. As much as 20cm could fall in the Ottawa Valley. For that reason and the fact the snow is coming during the start of the busy holiday travel period, the advisories were issued. Roads will become slippery and in many cases snow covered. Temperatures will remain cold with this system, so the precipitation will remain as snow for the duration of the event. Highs will be -5C to -7C Monday and Tuesday, with morning lows in the minus teens on Christmas Day. 

Travel conditions will be poor areawide Monday night, but will improve rapidly from west to east on Christmas Eve Tuesday.

Winter arrived in the pre-dawn hours Saturday, and along with it came the coldest air of the season. The morning low in Montreal on Saturday was -15.9C (4F), dropping to -17C (2F) Sunday morning. Gusty west winds produced wind chill values in the minus 20s at times Saturday.

We expect another cold night Sunday into Monday morning, as arctic high pressure crests over the region. If we reach -18C (0F) or colder Monday morning, it will be the lowest temperature recorded since February 25, 2023 when Trudeau Airport dropped to -20.4C. During the entire winter of 2023/2024, Trudeau Airport did not report one low temperature at or below -18C (0F).

Skies should clear out on Christmas Day, with sunshine forecast, but cold highs near -10C (14F). Temperatures will moderate for the balance of the week, reaching the freezing point by the weekend.