Early Fall Yellowstone Fishing Trips

Posted on January 25th, 2024 in Fishing Tips

fall brown trout, angler, and guide

For most visitors, fall-run brown trout are a focus in early fall. We’re not immune, but we try to dodge the crowds nowadays.

Introduction to Early Fall Yellowstone Fishing Trips

Early autumn in Yellowstone, generally meaning the month of September after nights start getting cold but the first heavy low-elevation snows have not fallen, offers the widest range of fishable waters of any season. Except for most small streams, which get too low and cold, virtually all water in Yellowstone Park can fish well in early fall.

For those who like match-the-hatch mayfly fishing, this is an ideal period, since mayfly hatches abound on all larger streams. It’s also a good chance for those who are willing to get out first thing in the morning or during the ugliest weather to get some of the biggest brown trout of the year.

The downsides are continued crowds near the road and inconsistent conditions. While overall crowds do decline, especially after September 15, these crowds slant older and less-fit, which means that the roadside easy-access streams can be more crowded now than earlier in the season, especially when the weather is nice.

Speaking of the weather, it might be beautiful and sunny or spitting bitter cold rain or snow. These varying weather (and water) conditions also mean that on our early fall Yellowstone fishing trips we have to play where and how we fish by ear, based on what fishes well given the day-to-day or even hour-to-hour conditions.

fishing guide filled with ice

Ice in the guides first thing in the morning, but warm afternoons, are common in early fall.

Early Fall Yellowstone Fishing Trips: Quick Facts

  • Best Waters: Rivers are better than small streams and lakes in early fall. Otherwise, the best waters depend on angler goals. The Yellowstone River remains a great choice regardless of weather for anglers eager to catch cutthroat trout in remote settings, while the Lamar and Slough Creek offer technical dry fly fishing as long as the weather isn’t too warm or too cold. When the weather’s ugly, the Firehole, Gibbon, and upper Madison turn on in a big way, and fall-run brown trout numbers steadily improve on all rivers that host them.
  • Three Top Reasons to Come in Early Fall: 1.) Excellent mayfly hatches occur on most rivers, even rough-and-tumble water where hatches are otherwise unimportant. 2.) A huge variety of rivers are available; September is typically the month when all rivers in Yellowstone Park produce, though not all on the same days. 3.) Fall-run brown trout fishing gets better and better as the month progresses (and the worse the weather gets).
  • Three Top Reasons to Avoid Early Fall: 1.) Gentle rivers and streams within 1.5mi of the road are unbearably crowded, especially before the typical mid-September cold snap. 2.) How well specific rivers and techniques produce depends hugely on weather. This is a poor time to come if you’re set on fishing one particular river or using one particular technique. 3.) The weather can be bright and beautiful, cool, drizzly, and unsettled (which is best for fishing), or miserable enough to make fishing impossible due to cold weather or muddy water. This is not autumn as it’s thought of in many parts of the country.
  • Perfect Clients: Early fall is a great choice for experienced and adaptable anglers willing to fish the rivers likely to fish well and use the techniques likely to produce given weather and water conditions.
  • What Early Fall Does Best: Early fall offers exceptional variety in river fishing, from small fish sipping tiny BWO mayflies on the Firehole on up to big cutthroats eating streamers on the Yellowstone.

September Trips: The Details

Sometime between August 25 and September 10, the nights start getting frosty while the days remain warm. This begins to change the options and techniques on walk-wade guided trips in Yellowstone. The small streams start to falter, as do the heavily-pressured meadow waters next to the road like Soda Butte Creek.

The bigger and rougher waters remain good, though early morning is seldom worthwhile except when anglers are hunting a couple big fish on nymphs and streamers rather than a bunch of little ones on dries. Thankfully, big fish opportunities increase at this time, as large numbers of brown trout begin moving towards their October-November spawning areas, prompted by cooling water. Dry fly fishing switches from better in the mornings and early afternoons to typically better from noon until roughly 5PM, and terrestrial insects and lingering summer mayflies are joined and soon replaced by heavier hatches of autumn insects.

fall cutthroat trout

Fall cutthroat are usually in very good shape and feed well on dry flies and streamers.

This is an excellent period for walk-wade trips for clients who want to use a variety of tactics. Probably our most common wade trip destination at this time is the Grand Canyon of the Yellowstone River. We tend to fish streamers in the mornings in September (sometimes racking up huge numbers), then switch over to dry flies in the afternoon. Since the water is much lower here at this time than in the summer, the fishing is slower-paced and we often wade-fish good runs and riffles for an hour or more, rather than bouncing from spot to spot.

Fall-run brown waters tend to be crowded at this time of year. On some, getting to the water at dawn is half an hour late to stake out your favorite spot, even though legal fishing hours don’t start until dawn. As such, we no longer focus on the run-up fish like we used to. When we do target them, we like to hit the secondary spots and secondary waters, aiming to surprise a few fish in uncrowded conditions rather than pounding the well-known holes. This tactic is most common on the Gardner River, where the rangers now sometimes scope the well-known spots with night-vision goggles to catch poachers. No thanks to those spots!

As early autumn progresses, the Gibbon and Firehole rejoin the party, though we seldom guide on them when rain and early snow (yes, it can happen in September) muddy the water closer to home.

angler streamer fishing on the yellowstone river

Streamer fishing is a good tactic on the Yellowstone in September.

Early fall typically offers very good fishing on walk-wade trips, especially for anglers with a bit of know-how. That said, it’s also an inconsistent time of year, primarily due to weather and water conditions. When it’s abnormally hot and bright, the mayfly hatches might not occur. Cold weather is better, but if this cold is accompanied by too much rain and snow, most of the good waters get muddy for a day or two.

Because of the lack of consistency, we encourage anglers considering early fall Yellowstone fishing trips to stay flexible. Walk when and where the walking is good and use the techniques the trout demand. If it looks like another one of our guided trips will be more productive, don’t hesitate to switch.

Full-day or half-day hike & wade trips make sense in this timeframe. Unless we’re looking for a few big ones early, there’s often no reason to start full-day trips before 9:00, especially later in September. The fall-run browns are the exception. If we decide to risk the crowds (we might want to try it on cold, wet, nasty days), we want to be on the water at dawn for either full-days or half-days.

Half-days in which we’re not chasing browns can meet at a far more civilized time, around 11:00.

Early autumn is not a great time for beginners to take walk trips unless they’re prepared to only get a few bites and mostly want to focus on learning rather than catching a lot of fish. Beginners typically catch FAR more fish on our float trips this late in the season.

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angler fishing good brown trout pool

When targeting fall brown trout in September, look for spots like this. This one only lasted two seasons (this go-round, it has formed and disappeared several times) before the river changed configuration, which is one reason we’re willing to show it to the Internet.