We were booked on a Polar Bear caravan a few years ago. The winter before our scheduled trip we were camped for 2 months beside a couple who resided in Churchill for 8 years. When we told him the dates of our trip, he shook his head and said no way would he spend the money to go that early in the year. He recommended flying up in November at the earliest. With thanks to him, we cancelled out scheduled caravan. Friends did go on the trip and did see about 6 bears, many of them off in the distance. They were quite disappointed but got to cross Churchill off their bucket list.
So far, we have not taken a flight to Churchill - it is still on our list!