Winter tires in Canada

The British Columbia government says winter tires or chains are required on most routes from October 1 to April 30. Requirements on select highways outside mountain passes or high-snowfall areas end March 31. Regulatory signs identify the designated routes.

For cars and light trucks, British Columbia accepts mountain snowflake tires or all-season mud and snow tires marked M+S. Either must have at least 3.5 mm of tread depth across the whole tire. The government recommends mountain snowflake tires for cold-weather driving.

Many coastal areas have no winter tire requirement, including parts of the Lower Mainland and southeastern Vancouver Island. That does not cover every nearby route: the government identifies the Malahat as a place where winter tires are needed. Municipalities and private roads may have different rules.

• Summer tires are not permitted during designated winter months on signed highways.
• Chains on summer tires do not substitute for winter tires on signed highways.
• British Columbia requires at least two matching winter tires on the primary drive axle, including on four-wheel-drive vehicles.
• The government recommends four winter tires evenly matched in tread type and depth.

The Société de l’assurance automobile du Québec (SAAQ) states that the December 1 to March 15 period includes both dates. It covers Quebec-registered motorized road vehicles, with specified exceptions. Rental passenger vehicles, mopeds, motorized scooters and motorcycles are included.

The Quebec government says the requirement does not apply to trailers or vehicles registered outside Quebec. SAAQ lists exceptions including heavy vehicles, tool vehicles, farm machinery and spare tires. Other limited exemptions also apply; SAAQ can issue a seven-day winter tire exemption certificate.

SAAQ says qualifying winter tires carry the official mountain snowflake pictogram or are studded. M+S marking alone is not one of those qualifying categories. SAAQ recommends at least 4.8 mm (6/32 in) of tread across the entire width when winter tires are installed; this is a recommendation, not the mandatory seasonal period.

The Ontario government advises drivers to look for the peaked-mountain-with-snowflake logo. It recommends installing winter tires in sets of four and not mixing tires with different tread patterns or sizes.

Ontario also advises replacing tires worn close to their tread-wear indicators. The tread-depth reference explains how tread depth is read. These Ontario recommendations are separate from the provincial winter tire requirements described for British Columbia and Quebec.

Under 49 CFR 571.139 (FMVSS No. 139), a snow tire attains a snow traction index of 112 or more compared with the ASTM F2493 standard reference test tire. A tire meeting that definition may display the mountain-with-snowflake pictograph at the manufacturer's option. This is the symbol commonly called the three-peak mountain snowflake.

British Columbia describes M+S as an all-season mud and snow marking and accepts it for cars and light trucks when the tread requirement is met. Its government page includes all-weather tires among mountain snowflake tires and says that category offers better traction on snow and ice. The all-weather name alone is not the marking to check: look for the symbol required by the applicable provincial rule.

For winter tires specifically, SAAQ says their rubber compound is designed to meet flexibility criteria at temperatures as low as -40°C. A tire's marking and the province's requirements answer different questions. British Columbia's acceptance of M+S does not make M+S alone a qualifying winter tire in Quebec.