Bighorn on the Brain: Updates for Montana’s Premier Tailwater, Aug 16-23, 2026

If you’ve been waiting for prime tailwater conditions on Montana’s Bighorn River, set your alarm and pack your fly boxes. The latest intelligence from Fly Fish Food reveals the river is locked into its sweet spot below Yellowtail Dam.

The River Conditions

The Bighorn is behaving exactly like a high-grade tailwater should:

• Flows & Clarity: The river is cruising along steadily. According to Fly Fish Food, “recent reports put flows around 1,000–1,500 cfs with clear water below Yellowtail Dam — classic tailwater summer conditions.”
• The Atmosphere: Expect afternoon highs in the low 80s with manageable breezes. Keep an eye on localized cloud cover, as “a slight storm chance Sunday night could briefly improve dry-fly action.”
• Water Clarity: Crystal-clear tailwater releases mean long leaders, subtle presentations, and precise drifts are non-negotiable.

The Bug Menu & Daily Playbook

Trout on the Bighorn run on a strict schedule. Dialing into the right insect at the right hour is the difference between a bent rod and a long day of casting practice:

• Early Morning (6:30 AM – 9:30 AM) | The Trico & Midge Frenzy: Wake up early. Heavy Trico spinners (#20–24) and midges bring fish to the surface before the sun heats up the riffles.
• Late Morning to Early Afternoon (10:00 AM – 3:00 PM) | PMDs & Black Caddis: As the morning warms, switch over to Pale Morning Duns (#16–20) and heavy Black Caddis (#16–18). If trout refuse the dries, drop a Tungsten Tailwater Sowbug (#10) or a micro Pheasant Tail (#20) below the riffle breaks.
• Late Afternoon & Evening (4:00 PM – 7:00 PM) | Hoppers to Olives: Fly Fish Food recommends keeping your options open late in the day: “Afternoon hopper action along grassy banks transitions to a late BWO window — stay mobile and match what fish are keying on.”

Box Staples for the Day

• Corn-fed Caddis (CDC) Peacock (#18): Perfect for skate-and-twitch takes during midday caddis flights.
• Tungsten Tailwater Sowbug (#10): The bread-and-butter meat fly for deep seams and drop-offs.
• Tungsten Pheasant Tail (#20): Micro-profile nymphing to pick off finicky subsurface cruisers.
• Terrestrials & Baetis Dries (#12–22): For pounding the cutbanks in the late afternoon heat before swapping to delicate emergers at dusk.