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. 

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. 

Yes dropping to a smaller winter tire size (called “downsizing”) is safe if it’s done correctly, and it can save you money.  

Why it’s safe (when done properly) 

• Manufacturer-approved fitment: You need to choose a size recommended for your vehicle (usually listed in the owner’s manual or by tire professionals). 
• Same overall diameter: A smaller rim size usually means a taller tire sidewall, so the overall tire diameter stays close to your original specs. This keeps your speedometer, handling, and safety systems accurate. 
• Better winter performance: Narrower tires perform better in snow and slush, since they cut through instead of floating on top. 

How it saves money 

• Cheaper rims: Smaller steel rims cost less than large alloy rims. 
• Lower tire price: Smaller-diameter tires are generally less expensive to purchase. 
• Long-term savings: Keeping your nicer summer rims stored protects them from winter salt and damage. 

Things to watch out for 

• Don’t go smaller than what’s recommended for your vehicle. 
• Make sure you maintain the correct load rating and speed rating. 
• Always get professional advice before choosing a different size. 

In short: Downsizing to a smaller winter tire size is not only safe, but also often recommended and can save hundreds of dollars over the life of your tires. 

Winter tires can affect EVs a little differently than gas-powered vehicles because of how EVs use energy and deliver torque. Here’s what to keep in mind: 

1. Range Impact

• Winter tires usually have a softer rubber compound and more aggressive tread, which can slightly reduce efficiency. 
• On an EV, that translates into a noticeable drop in range (often 5–10%, depending on driving style and conditions). 
• Cold weather itself already reduces battery performance, so the effect adds up. 

2. Weight Considerations

• EVs are heavier due to their batteries. That extra weight puts more demand on tires, especially in winter braking and cornering. 
• Choosing winter tires specifically rated for EVs (with stronger sidewalls and higher load indexes) helps manage that stress. 

3. Instant Torque & Traction

• EVs deliver torque instantly, which can cause more wheel spin on ice or snow. 
• Proper winter tires help control that torque and improve grip, especially when accelerating from a stop. 

4. Regenerative Braking

• Regenerative braking can cause wheels to slip on icy roads if traction is poor. 
• Winter tires reduce that risk, allowing regen to work more smoothly. 

5. Noise Levels

• EVs are quiet, so you’ll notice tire noise more. Some winter tires designed for EVs are optimized for low rolling resistance and reduced cabin noise. 

Bottom line: winter tires are even more important on an EV because of the vehicle’s weight and instant torque. Yes, you might lose a little range, but you’ll gain far better safety and control.