Yep, below freezing has a big impact on battery drain. Expect to cut the range estimate by a third and make sure you keep a decent level of charge in the car for general drain.

There are plenty of people that use EVs in these conditions, but you do need to be aware of this. 

Petrol cars have the advantage of producing heat as a waste by product of their fuel explosions. EVs use electricity to heat the car which is inefficient compared to petrol. Modern EVs use heat pumps which are more efficient, but you still can't beat the heat produced by a petrol car which has no effect on range.