Quebec Tire Regulations

In winter, drivers must adapt their driving to weather and road conditions. Winter tires are mandatory from December 15 to March 15 inclusive. If your vehicle is not equipped with winter tires between December 15 and March 15 the fine varies from $200 to $300, plus costs. For better traction, the tread depth of your tires must be at least 4.8 mm (6/32 in) when they are installed.

Even though legislation allows for the use of tires with a tread depth of only 1.6 mm (2/32 in), below 4.8 mm (6/32 in) you may be compromising your safety. Chains and studs are prohibited on heavy trucks. The Minister of Transport may authorize, under the conditions and for the period he determines, the use of certain types of non-skid devices for such road vehicles as he may designate.

https://saaq.gouv.qc.ca/en/road-safety/behaviours/adapting-your-driving/winter-driving/