Actually, I think the climate on the south side of Lake Ontario is a bit warmer and wetter (thus the lake effect snow). The cold air is moderated a bit as it crosses over the lakes, but it also picks up all that moisture. In fact, I think the windward side of all the Great Lakes are similar and might be in different climate zones vs the leeward side of the lakes. I know in Western Michigan for example there is a bit of a fruit belt because of this.