We are based near Ottawa, Canada...30 minutes north near Wakefield, QC...and we've had our Clarity since July 20, have put on 9200km and I've spent $82 on gas (4 fill-ups, the result of 2.5hr road trips to Montreal).
The cold weather has kicked in here, for sure. So, during summer and warm fall months, the highest range I got was 92km (sorry...we're in kms here!). At this time of year, I am averaging 55-65km. This morning it is reading "full" -- according to my juicebox charger app -- at 56km. Last night was a chilly -17C. I have been told it can go as low as 40km. I know...a far cry from 92km, but we are still able to run fully on electric (except for those road trips!) by planning and plugging in at charging stations. So, yes, the drop in range for your car sounds reasonable to me.
The issue with the ICE kicking in is interesting. I haven't experienced it, but my husband did a few weeks ago when he went to pick up our daughter late at night...only about 12km away (we live in the country, btw!). He said, like you, it was very strange. Battery was full, but the engine came on....and then went off later. I have no idea what this is but wonder if it's just the car "running" the engine because it hasn't been run for a while (oil circulation thing? have no idea!), or possibly related to cold temps? Though I doubt the latter...as last night was our coldest yet at -17C and I drove all the way home from the theatre (45km) on electric, even after setting the car to warm up (precondition) half an hour before the show ended (so nice to hop into a warm car, I have to say!).
Not sure if that is any help! :-)