The biggest drop I've seen on my 2017 GOM is 26% less range in 0F/-18C and using snow tires. If my battery is 30kwhr, then that's about 7.8 kwhrs of "penalty" for being winter, spent over about 90 minutes of driving (5.2 kwhrs extra per hour of driving). I think that matches reports of the inductive heater?defrost pulling as much as 5kw.
If you had a 30kwhr battery (2016/2017), and it was degraded 30% over 5 years (effectively 21 kwhrs), and you wanted to arrive home at about the "Very Low Battery" alert (7%-8%, or 1.6kwhrs), then you have about 124 km's of range at 96 km/hr, according to Tony's chart. If your commute took 90 minutes total, you might subtract about 7.8 kwhrs for heating, or 37% of your capacity, yielding about 78 km. (37% range loss for heating/snow tires on a 30kwhr Leaf also sounds reasonable to me, based on other reports).
So even with a late-model 30kwhr Leaf, with the heat-pump, that's the case where you would still not have enough range for your commute (you may be short by 19 km):
- the battery has degraded by 30% (maybe 5-7 years after manufacture, in your climate)
- it's -18C and you're using snow tires, plus some loose snow on the roads
- no preheating
The easiest way to improve this is to preheat the car while plugged into a L2 charger at home. If the car is toasty and 100% charged when you depart for work, I doubt that the heater would pull more than 3kw, saving you about 3.6kw on the way to work. That's enough for 16 extra kilometers.
A second way to improve would be to slow down to 90 km/hr on the coldest days. An 8km/hr slowdown should get you an extra 12 km (per Tony's sheet).
A third improvement would be to get a plug at work (even a 120v, 12A plug at the lamp-post would add 7km per hour). I don't think this would be necessary until range has degraded by 30%, so you wouldn't need it for several years.
My guess is that, provided that you preheat before departure, a 2016/2017 Leaf with heat pump should work without a plug-in at work until it's 3 to 5 years old. Years down the road, when the car is 30% degraded, then some kind of plug-in at work would be necessary. If that outlet is not in the cards, then the Volt is also an excellent choice. (Though the Volt would benefit even more from a workplace charging outlet).
FYI, my pack is at 2.3% degradation after 19 months in Minnesota. Our weather is about the same (-9.1 C vs your -4.7 C daily mean in Jan, 23.2 C vs your 22 C daily mean in July). I am not expecting to see 30% degradation until 6.5 years (winter 2023/2024 for a 2017; a year earlier for a 2016), based on comparing my numbers with FlipTheFleet.org charts. If you're buying used, be sure to buy a Leaf used in Canada, and not something trucked-in from Arizona (not sure if they do that). If I were you, I'd probably be looking at 2016 Leaf SLs, or SV with heat pump (may be hard to find). If I were buying new, I'd either look at a 60kw+ car (Bolt, Niro EV, Kona EV, Soul EV) or wait for the 60kw Leaf.