We climbed it in the summer of 1991, I recall seeing some signs with details on the deaths (back then) of over 100 hikers and most of the dates that they perished were either in May-June or October-November. I suppose from December to April there is too much snow at lower levels to invite anyone to start out (although well equipped hikers do venture up in the winter season).
A few of the deaths were caused by flash floods at night, camping in a gully near a roaring mountain creek might seem attractive as long as there isn’t a thunderstorm. Those creeks can overflow in a matter of minutes. Most of the deaths occur about two thirds of the way up when hikers are out beyond the tree cover and into the tundra environment near the top. The climate at the summit is not a lot different from central Labrador or northern Quebec and may even be colder in the summer months.
On some of those deaths, a sudden white out happens and they get confused and go down the wrong side into no mans land.