It gets to -35C where I live during winter. I have an unheated garage and park outside while at work, I have an EV and definitely see a drop in range but it isn't large. I can still drive around 300 km on a fully charged battery while using heat.

I can get more range by being more sparing with my heat, if I just use my heated seats and steering wheel I can keep the heat on less and get about 50 extra kms. My trips are pretty short so a fully changed battery lasts me 3 weeks during summer and 2.5 weeks during during winter.