Calgary's snow season is long and its edges are blurry. In a typical year the first snow that sticks arrives in October, the last in April, and the deepest snow on the ground is a midwinter matter. But Calgary regularly gets flurries in September and again in May or June, and neither is considered remarkable here — a September snowfall on leafy trees is a recurring local event, not a freak one.
Two things. First, it rarely accumulates for the whole winter the way it does further east: chinooks repeatedly melt the snowpack off and then let it refreeze, so Calgary sees far more bare-ground days midwinter than its latitude suggests. Second, the biggest snowfalls are often spring events. A wet, heavy April or May snow — the kind that breaks branches and knocks out power — is a more realistic worst case here than a January blizzard.
Elevation does most of the work. Northwest Calgary — Edgemont, Nose Hill and the surrounding ridges sit roughly 100 m above the river valley — tends to see snow start earlier, accumulate more and melt later. The low, dry east side generally gets less of it and loses it sooner, partly because it is drier and partly because it warms faster once the sun is out.
The same storm can therefore leave a very different driveway in Edgemont than in Forest Lawn, which is worth checking before you decide whether to shovel or wait.
If you are driving west, do not use Calgary's forecast. Canmore sits a few hundred metres higher in the Bow Valley and Banff higher still — both get snow earlier in the autumn, later in the spring, and can be snowing while Calgary is dry and mild. Highway 1 through the Bow Valley can change conditions within a few kilometres. Check the destination, and check Alberta 511 for road conditions before a winter drive.
Snow tires are worth having on from October to April here, less for snow depth than for the ice that the freeze-thaw cycle produces. Calgary's sidewalk-clearing bylaw puts the responsibility on property owners within a set window after a snowfall, so it pays to know the current rule. And because a chinook can arrive within a day, clearing snow before it turns to ice is usually less work than dealing with it after.
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