Once the heat of summer fades and into September the size of the insects available to trout decreases. Blue Winged Olives, October caddis, and the occasional midge dominate the Yellowstone’s fall hatches. Because of the lack of prolific fall hatches trout on the Yellowstone remain opportunistic and a well-presented general attractor fly will often produce. However, the lure of a trophy trout from September through November causes most anglers to drop the dries and head right for their streamer fly box.
On the Yellowstone the fall season is clearly the season to fishing nothing else than streamers, wolly buggers, and other baitfish imitations. In most years the largest fish on this river are caught during two time periods: the salmon fly hatch and the fall when bigger fish are on the prowl for little fish. And of the rivers biggest trout taken on a fly in the past fifty years most have been caught in October or November. Add the beauty of the changing cottonwoods, lack of summertime pleasure floaters, and the possibility of a lifelong monster trout and the Yellowstone shoots to top of any anglers wishlist of Montana rivers.
From late November and into March the Yellowstone’s many local anglers look elsewhere for their fishing opportunities as cold water temperatures, wind, and lack of consistently feeding trout gives little reason to hit the water. Plus with several quality ski resorts nearby most locals are on the slopes, not streamside.