Bighorn Riches: August Flies and Trophy Trout on Montana's Tailwater

Artificial Lure here with your Big Horn, Montana fishing report for August 10, 2025. Grab your rods — it’s shaping up to be a classic August day on the Bighorn River and nearby waters. Weather’s off to a crisp, sunny start, with highs on the river forecasted for the upper 80s to 90, and just a bit of breeze out of the northwest. Overnight lows slip down to around 60, so the river will keep that cool bite in the morning. Watch for scattered afternoon thunderstorms rolling through, especially later in the weekend, but most mornings should be clear with visibility for miles. Sunrise is at 5:37 a.m. and your evening window will tail off around 8:32 p.m., so there’s plenty of daylight to chase a trophy. This time of year, the Bighorn’s tailwater is running steady and clear, with no runoff issues — perfect conditions for both wading and floats. Recent reports from locals and guides say the river’s loaded, with an average 4,000 to 6,000 rainbow and brown trout per mile. August is a favorite for dry-fly fanatics and hopper action. Tricos are in full swing most mornings, clouding over riffles right at sunup, and the black caddis are thick along grassy banks by mid-morning. Yellow Sallies are still lingering, and hoppers are firing, especially midday when that sun’s high. Recent catches have ranged from chunky browns in the 16 to 20-inch class to hard-fighting rainbows pushing 18 inches or better. Top patterns right now are small Trico spinners (size 20-22) for the early bug soup, black caddis (size 16) as the sun warms, and hopper-dropper rigs through the heat of the day. Try tan and pink Chubby Chernobyls (#8-12) or a classic Dave’s Hopper. Trail your hopper with a beadhead Pheasant Tail or Zebra Midge to suss up those suspicious feeders. For sub-surface, don’t overlook a sowbug in the faster water. The lower Bighorn is producing the biggest browns — float between Bighorn Access and Mallards Landing, and look for shaded banks and inside bends. After lunch, fish are sliding into cover and holding deep, so switching to small streamers like an olive Sculpzilla or a thin-mint Woolly Bugger could net you a brute, especially if we get a quick thundercloud and the light dims. If you’re after numbers and steady action, stick to the upper river above the 3-Mile Access, where pods of rainbows are chasing sippers in the seams. Eagle Nest Lodge notes the entire river is fishing well, but you'll often have the lower stretches nearly to yourself this month — and that’s where the browns get mean. Bighorn Lake is steady, too, hosting healthy populations of walleye, bass, and plenty of panfish. The mornings have seen good walleye bites along drop-offs using nightcrawlers or leeches on bottom bouncers, while rocky points on the south end are producing smallmouth bass on crankbaits and jerkbaits, especially early or late in the day. No tidal changes to worry about — just keep an eye out for those surprise afternoon gusts that can whip up chop. No unusual restriction This content was created in partnership and with the help of Artificial Intelligence AI.