Producing a time-lapse video over 6 months or more
Finding specific models is outside the scope of this site as the ideal available models will change regularly, but you will probably want to look at a security camera to fill this roll.  Not a lot of cameras are designed to operate reliably in harsh conditions over long periods of time.  Outdoor security cameras are.

The next biggest problem is going to be the lack of power and the cold temperature.  Batteries do not work well at low temperature and if it is below freezing, you are going to see drastic reductions in battery efficiency making it difficult to keep the camera running.

You might also try outdoor hunting webcams.  They tend to be used to take photos at a slower rate and have more battery powered options. These might also work for your purposes.