When should I switch to winter tires in Ontario?

Watch the thermometer, not the snow

Winter tires are not snow tires — the name change happened for a reason. The real difference is the rubber compound. All-season rubber starts to harden below roughly 7°C, and hard rubber grips cold pavement poorly whether that pavement is dry, wet or white. Winter compounds stay soft and keep biting in the cold.

So the trigger is temperature, not the forecast for flurries. Once daytime highs — not overnight lows — sit consistently below 7°C, your all-seasons are already giving up grip on every morning commute, and the swap is due. Waiting for the first snowfall means driving weeks of cold-and-hard on the wrong rubber first.

What that means in the GTA

Around Markham and the rest of the GTA, the useful planning rule is simple: book in October and aim to complete the change by November 1. That is Taylor Tire’s weather-and-scheduling target, not one deadline shared by every insurer.

Book early and you can choose the day and time. The changeover itself takes about 15 minutes ($50 – $140 a set, posted on the rate card); if you still need tires, start sooner because popular winter tire sizes sell through first. A quote costs nothing, and the insurance-discount guide explains the paperwork.

When 7°C actually arrived in Markham — the last five years

Recomputed on 2026-08-12 from the Open-Meteo Historical Weather API at the Markham coordinates 43.8561, -79.3370. For each fall, we found the first single day when every morning and evening commute hour (7–9 am and 6–9 pm) was below 7°C:

All five years reached that point by November 1. Treat the data as a planning cue, not permission to wait: book in October and aim to complete the change by November 1.

Why the first snowfall is the worst day to call

Every fall it is the same story: the first real snow lands, and by mid-morning every tire shop in the GTA — ours included — is booked out days or weeks deep. Everyone who waited calls at once. The people sliding through that first slushy commute are the same people who could have swapped calmly two weeks earlier, on a day of their choosing.

There is no prize for squeezing the last mile out of your all-seasons. The cold arrives before the snow does, so by the time the snow is the reminder, you are already late — and now you are late together with everybody else. Book on the thermometer and the first snowfall becomes someone else's problem.

Switching back in spring

Same rule in reverse: once daytime highs stay above 7°C — typically April in the GTA — it is time to put the summer or all-season set back on. Soft winter rubber wears faster on warm pavement, so leaving winters on into late spring quietly eats a season or two of their life.

Don't jump on the first warm week of March, though — a mild spell followed by a cold snap is classic Ontario. And if you claim the insurer discount, the swap-back date isn't really yours to pick — that's the next section. When the winters do come off, we can keep the off-season set here — see tire storage and how to store tires properly if you keep them at home.

Insurance dates vary by policy

The thermometer and your insurer answer different questions. The 7°C rule tells you when winter tires become useful; your policy tells you which calendar period is required for the discount. There is no single Ontario-wide insurance deadline.

Published examples show the difference: TD publishes December through March, while Allstate publishes November through April. Other insurers may use other wording, and the terms in your own policy control.

For cold-weather grip and an easier appointment, Taylor Tire recommends booking in October and aiming for November 1. For discount compliance, confirm the exact installation and removal dates with your insurer or broker. The insurance-discount guide compares the published rules.