Bighorn River Report: Crisp Fall Fishing, Nymphing Hot, and Crowds Thinning Downstream

Good morning folks, Artificial Lure here with your September 27th, 2025 angling report for Big Horn, Montana. It's another crisp start on the Bighorn River, with sunrise peeking over the cottonwoods at 7:01 AM and sunset coming just after 7 PM. We’ve got classic fall weather—overnight lows in the high 40s, a light fog burning off by mid-morning, and daytime temps headed for the mid-60s. Expect a bit of wind out of the northwest later on, nothing outrageous, just enough to make those long leaders dance. No tides to report on the Bighorn, just steady cold flows rolling out from Yellowtail Dam. That tailwater is cranking out gin-clear, chilly water, keeping trout lively from first light through evening, according to Bozeman Montana Fly Fishing. You’ll want to be on your toes today, as the best bite changes by the hour. Surface activity has tightened up, but don’t stash those dry flies just yet. There are still good windows—especially mid-morning and right before dusk—where you’ll catch steady risers in the slicks and soft edges. PMDs (Pale Morning Duns) are hanging on, so pack your favorite Rusty Profile Spinner, PMD Crackback, or a classic PMD Jigster. For the last hour of daylight, fish are keyed in on spent spinners, so keep your eye on gentle water near the banks. The main story is below the surface. Nymphing remains hands-down the most effective method right now. Go with double rigs: tailwater sowbugs, orange scuds, rubberlegs, and smaller midge patterns like the Black Zebra Midge. Pair those with a small perdigon or leech, and work deeper seams and drop-offs. Depth and drift are critical—adjust your indicator and cover water until you find where they’re stacked. Throughout the afternoon—especially as the sun gets high—focus on riffles and tailouts for trout feeding on caddis pupae. Caddis are providing some of the day’s hottest action, so don’t overlook those seams by the Afterbay and Three-Mile sections. Rubberlegs and small midge nymphs mimic what they’re eating. We’re still seeing a few hoppers and ants along the grassy margins, but they haven’t turned into the main menu yet. You might piqué some interest near undercut banks or in the wind lanes, so it’s not a bad idea to try a Sweetgrass Hopper or big ant pattern in those zones, particularly on days when the wind kicks up. Streamers are a dark horse; early or late, swing a black bunny leech or something with flash along the rocks or woody structure for a bonus brown. The action this week has favored wild browns and rainbows in the 14 to 18-inch range, with a handful of bigger slabs mixed in—especially from the legendary Breakfast Hole down to the Hot-Dog Run, a stretch known for holding good numbers and size. Crowds thin as you float downstream of Bighorn Access, but the fish are there for those willing to put in the oar time. For the roving angler, top hotspots today are: - Three-Mile to Afterbay—prime seams, riffles, and side channels for numbers and size, with good wading opportu This content was created in partnership and with the help of Artificial Intelligence AI.