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, daytime highs usually settle below 7°C somewhere between late October and November. That is your window. Some years it comes early, some years late — watch the two-week forecast rather than the calendar.

Our advice from the counter: book in October, before the window opens. Early birds pick their day and their time slot, and the changeover itself takes about 15 minutes ($50 – $140 a set, posted on the rate card) — outside the rush the wait is an hour at most, usually less. If you still need the tires themselves, start even earlier — popular winter tire sizes sell through first, and a quote costs nothing. Running winter tires also unlocks the Ontario insurer discount — here is how to claim it.

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

Computed from hourly Markham weather data (Open-Meteo — the same source as the forecast on our booking page). Two thresholds, because most driving happens on the edges of the day: the date the morning and evening commutes (7–9 am, 6–9 pm) went below 7°C for three straight days, and the date even the daytime high stayed below 7°C:

Read the left column if you drive to work or drive kids around after dinner — that is the temperature your tires actually live in, and in four of the last five years it arrived by November 1, as early as October 18. All-day cold follows one to two weeks later. Which is the whole case for booking in October: by the time the afternoon feels wintry, your commutes have been below 7°C for weeks.

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.

The insurance window: November through April

One hard constraint the thermometer knows nothing about: your insurance window. If you claim the Ontario winter tire discount, the tires don't just have to exist — they have to be physically on the car through a set stretch of the calendar. Almost no insurer publishes that stretch, but it is written down. This is the line a broker sees in their own quoting system when the discount goes onto a policy, verbatim:

Veh. must be equipped with 4 winter tires from Nov thru Apr.

Broker desk The working rule from a desk that submits these discounts every day: winters on by November 1, off no earlier than the end of April — every full month from November through April. Some desks wave you through from mid-April; the strict reading is April 30, and it only costs two extra weeks.

Do the exact dates vary by insurer? Yes, and it is genuinely murky — a couple have put dates in public (Allstate's own site says November to April; TD's article mentions December to March), but most write nothing, and the terms live in your policy wording. So don't shop for the shortest window. Nobody checks your driveway on November 2nd — this gets checked after a claim, when the file is read backwards, and a window you didn't honour becomes a clawed-back discount at the worst possible moment. When the weather and the policy disagree, the policy wins.

The consolation: the insurance calendar and the thermometer mostly agree. The temperature table above put commute hours below 7°C by November 1 in four of the last five years — the underwriters just wrote the physics down as dates. Which insurers credit which tires is its own guide.