When the outside temperature consistently drops below +7°C, it’s time to switch to winter tires. 

Why it matters: 

• Rubber performance – All-season or summer tires harden when temperatures fall below +7°C, reducing flexibility and grip. Winter tires are made from softer rubber compounds that stay flexible in cold weather.
• Traction and safety – Winter tires have tread patterns designed for snow, slush, and ice, giving better traction, braking, and handling. Even on dry, cold pavement, they outperform all-seasons below +7°C.
• Braking distance – Stopping distances are significantly shorter with winter tires in cold conditions, lowering accident risk. 

In short, the 7-degree rule ensures you’re switching tires not just for snow and ice, but for cold weather overall—boosting safety, control, and confidence on the road. 

In Ontario, the general guideline is to install winter tires when the temperature consistently drops below 7°C. That’s when all-season tires begin to harden, reducing traction, while winter tires stay flexible and maintain grip. 

Here’s a practical timeline for Ontario: Late October to mid-November → Ideal time to switch, before the first major snowfall. 

 Keep in mind: Winter tires aren’t just for snow—they’re designed for cold, icy, and slushy conditions, giving shorter stopping distances and better control. 

You should always install four winter tires, not just two.  

Here’s why: 

Two tires only (front or back) → Creates a major imbalance. You’ll either have good traction in the front but sliding in the back (oversteer), or grip in the back but poor steering and braking (understeer). 

 Four tires → Keeps handling, braking, and traction consistent on all wheels, which is critical on icy, snowy, or slushy roads. 

In fact, Transport Canada and the Tire and Rubber Association of Canada both recommend using a full set of four winter tires for maximum safety. 

Using only two is unsafe and can actually make winter driving more dangerous. 

In Ontario, having winter tires can earn you a discount on auto insurance—usually between 2% and 5%. 

 What you need to qualify to get the discount, most insurers require: 

•  A full set of four winter tires with the proper "mountain-peak + snowflake" winter tire symbol. 
• Tires installed by a certain date and kept on until a required end date. Typically, November to March or April. 
• Proof to the insurer (receipt, photo, or something similar) that the winter tires are indeed used.