The temperature difference between Port Arthur and Fort William, the two parts of Thunder Bay located 5 kilometres apart, is usually about 5 degrees, give or take. At this time of year, with a southerly wind, the difference could be nearly 20 degrees. Go inland to the next down, and it will be in the 30s while we flounder in the high teens. In fall and spring, one end of the city will usually have twice as much snow as the other. My neighbourhood sometimes has no snow left while the north end still has 3 foot tall snowbanks.
But I'm not going to go on about how our climate data doesn't apply because half the city is colder and wetter than the other half.
Toronto gets more snow because it is downwind of large water bodies. Thunder Bay gets less snow than Toronto because we don't have a giant lake for cold, dry air to grab water out of and dump it on us. The other side of the lake from us gets more than twice as much snow as we do, because there is somewhere for the snow to come from. Winnipeg gets even less snow than Thunder Bay because they have even fewer sources of moisture than us upwind of them in winter.
Vancouver, BC (technically, the Vancouver Airport in Richmond) gets more heavy snowfall events (40+ cm) than Thunder Bay.