I also had a bit of a strange experience: it was late Harvest month, the temperature seemed normal for that time of the year and my character was standing outside her cabin during the day, nothing unusual in her Warmth status (somewhere between Comfortably Warm and Hot - nothing to raise an eyebrow for). I saved the game, and when I returned, she was suddenly Bitterly Cold. The temperature bar was well into the red, again usual for Harvest month, so where this cold status came from ... no idea. However, after warming up by the fireplace, everything seemed to return to normal. Migrated character, WEATHER.DAT was deleted before the first migrated game was started.