By Brian McGeehan at Montana Angler Fly Fishing
September in the greater Yellowstone region is quickly becoming one of the most popular times to visit and fish. September is a great time to fish Yellowstone National Park because water temperatures are dropping into the optimal range and trout feel the urge to pack on the pounds for the upcoming winter. Weather in September is usually very pleasant with cool, crisp mornings and warm afternoons. September is the only month of the year when literally every river in the Park is fishable. The Madison drainage has cooled enough for productive fishing but the high country streams are still warm enough for fish to be active. Throw in a few bugling elk and some fall colors and you have the recipe for a great trip. Let’s take a look at some of the highlights of September fishing in the park.

Firehole River
As the weather cools, the Firehole once again becomes a viable option for fishing. At the beginning of the month, it may only be cool enough to fish in the mornings, but by the middle of September it should fish well all day. The main attraction during September is the White Miller Caddis, which typically emerges from mid morning until early afternoon. On cloudy days, especially towards the end of September, Blue Winged Olives emerge in the middle of the day. When no hatch is present, swing soft hackles through the riffles. I prefer drab, generic flies like a soft hackle pheasant tail or hare’s ear. In the fall, primarily due to low water, the fish in a Firehole can be a bit pickier than they were in June. Downsize your tackle a bit and take care not to spook fish with your movements.
Madison River
The main attraction on the Madison River in Yellowstone Park in the fall is the run of fish out of Hebgen Lake. While this run peaks in October...