EV range drops, sometimes quite a bit, in cold weather.
Temperature effects the battery chemistry, use of electric heating inside the cabin draws significant power from the battery, and use of snow tires further diminishes range.
The amount of range reduction can be quite a lot (30-40%) depending on where you live and weather and road conditions.
With about half of EVs registered in California (within the U.S.) the cold weather range issue is sort of ignored. At some point, this may be seen as a problem and one that is not yet solved. Trying to drive a 300 mile EV range car cross country in winter – or in Canada in winter – might mean very frequent charging stops, greatly increasing overall travel time. Seems like an issue that needs more discussion.
There is some discussion of the topic in this Chevy Bolt EV forum thread. But this is also covered in forums for all EVs.