Winter Tires in Toronto: When to Switch

The short answer

Switch to winter tires when the daily temperature sits at or below 7 degrees Celsius, which in Toronto is usually late October to mid November. Book the changeover before the first snow, because every shop fills up the week it arrives.

Why 7 degrees

The rubber in an all-season tire starts to harden as the temperature drops, and a hard tire has less grip on cold pavement, wet or dry. Winter tires use a compound that stays soft in the cold, with tread cut to bite into snow and clear slush.

That means winter tires help on a cold dry morning too. The reverse is also true: left on in warm weather, the soft rubber wears quickly, so take them off in spring.

How to check the tires you already have

Look for the mountain and snowflake symbol on the sidewall. It marks a tire tested for winter traction.
Check the tread depth across the whole width of the tire. Winter tires lose much of their snow grip well before they reach the wear bars.
Find the four-digit date code on the sidewall: the week and the year the tire was made. Rubber hardens with age even when there is tread left.
Look for cracks in the sidewall and for uneven wear on one edge.

Tires on rims, or tires only

A set of winter tires mounted on their own rims is quicker and cheaper to swap each season and spares the tires from being mounted and dismounted twice a year. Tires without rims have to be mounted and balanced at every changeover.

After the changeover

Tire pressure drops as the air gets colder, so check the pressures again after the first real cold snap.
Have the wheel nuts re-checked after the first 50 to 100 km.
If the tire pressure light stays on, your winter wheels may not have sensors, or the car may need to learn the new set.

Insurance

Ontario does not require winter tires on passenger cars, but insurers in the province offer a discount for using them. Ask your insurance company what proof it wants.