What is the ruling on traveling to another country for the purpose of fasting a short day in cold weather?

There is no harm in an intention like this. What is forbidden is to travel in order to break one's fast. The objective is to achieve the fast of the day, and that is why it is permissible to make up for a long day with a short day. So, if it is known that the length of the day is not intended, then it is permissible to travel to fast days that are shorter than those he fasts in his own country; because he has fulfilled the obligation properly and has fasted the month as commanded.