Torono isnt really typical. It is southern canada, and a bit of a heat island. Fort Mcmurray (that had to evac a few years ago) average january low: -22.5c. Places like that have almost 90c temperature swings from low to high in a given year (-50 to +35).
The Toronto region contains about 25% of the Canadian population, which is sufficient for my point.
Your attempt at nit picking, if it were valid, would actually makes it much worse: a temperature increase sufficient to turn "-22c" into "we don't need to worry about cold batteries" requires close to double the difference between today and the highest estimated average global temperature ever in the biological history of the planet, and that temperature happened before trees had evolved.
For example, naïvely adding 22 C (22.5 says Wiki) to the average so that the coldest was no longer below freezing, your Fort McMurray would have a new July average high of 46.2 C, which is above the current average of Death Valley 10 months of the year and pretty close the other two.
