Fall is doing its usual Yellowstone Country two-step, according to Big Sky Anglers‘ September 24, 2026 report. It is sunny and near 70 one day, gray and 50-something the next. Either way: “It’s going to be a fun week to be fishing around the Park.”
- Firehole — Daily baetis, rising fish, and trout that will quietly wreck your confidence. Long 10–12′ leaders, 5.5–6x, delicate drifts. These fish “will test your skill and humble even the most veteran anglers,” with the occasional 16–18″ bonus.
- Madison — Lake-run fish are trickling in and prime time is close. Sunny days mean dawn or dusk, with terrestrials in the Northeast Corner saving your afternoon. Ugly weather means fish all day.
- Gallatin — The week’s Swiss Army knife: “there may be no more versatile a river to fish than the Gallatin in the Park.” Hoppers and ants in the sun, baetis emergers under the gray, and excellent nymphing when nobody’s looking up.
- Slough, Lamar & Soda Butte — Terrestrial season is on life support, not dead. Sleep in, let the water warm, fish the afternoons — small hoppers, beetles, ants, plus Hecubas when it clouds up.
- Gardner — Hopper-dropper in the pocket water, with a few Yellowstone browns already starting to slide in.
The season’s whole mood in one line: let the day develop, and fish the warm afternoon hours. Are people really in a hurry in late September?
Big Sky Anglers — 39 Madison Ave, West Yellowstone, MT 59758 — (406) 646-7801
Montana Outdoor Weekly Pulse
Montana's outdoor week, in your inbox at 7am Friday.