Not sure what the ambient temperature was during that time, but that doesn't surprise me. Also, a 2 week difference could be a temp delta, which matters substanially for range. Add in city vs highway, and yeah that all checks out.

I'm assuming for a rental you probably got a 75D if it was made in 2017. Factory new, it had a range of 238mi EPA (383km). Assuming even 10% degradation (which is probably high, honestly) and only charging to 90%, that would give you 310km EPA. I'm guessing you wouldn't drive it all the way to 0 either, so you're really looking at 292km (if you leave 5% at the bottom).

Then add on winter driving at highway speeds that will indeed reduce range by as much as 30% (or even 50%, if it's truly frigid) and that isn't surprising at all. The Ioniq being driven in city mostly will vastly, vastly increase range. And modern cars (model X included) have heat pumps, which improves winter range substanially. The 2017 X would have purely resistive heating, which really hurts range in the winter.

This isn't unique to Tesla, by the way. F150 lightning owners have gotten pretty annoyed that the range is garbage during winter or during towing. Even the most efficient EV will struggle to get even 70% rated range with -20C or equivalent.