Introduction to Fly Fishing Montana in Late Fall
Fly fishing Montana in late fall can come as a rude awakening to anglers from warmer parts of the country. The period running from sometime in the last few days of September or early October through the middle of November will feel more like winter to these folks. Cold and wet weather is now the norm, and snow is very possible at any time. If you are contemplating coming during this period, ugly weather is one factor you MUST be willing to accept. Ugly weather often leads to the best fishing.
Late fall is brown trout season. Targeting these fish as they prepare to spawn is the number one option in the region at this time. Some options for dry fly fishing for other species still exists, but for most visitors, it’s a secondary option. The overall numbers of fisheries that make sense from a consistency perspective declines steadily through the period, and crumbles once Yellowstone Park’s season ends at sunset on the first Sunday in November. Crowds are generally gone except on the most-famous brown trout rivers (particularly the Madison). Elk are bugling. Aspens and cottonwoods turn gold in October, then fade to brown and bare limbs late in October. It’s a great time to be here if you like hunting larger trout and can handle the weather.
Weather and Water Conditions
Weather conditions can be warm, bright, and sunny, or it can be snowing sideways with temperatures below zero. Neither extreme is good for fishing. The best days will occur when daytime highs range from the high-30s into the fifties, under cloudy skies, with little or no wind. Average highs are in this ballpark, however it’s more commonly sunny and windy than cloudy and calm. Rain is more common at valley level than snow at least until the beginning of November, but mountain snows stick around from now until spring, and even in the valleys it will snow enough to stick around for several days from time to time.
I cannot overstate how important it is to be prepared for bad weather in late fall. Just about every year there will be at least one heavy snow event with Arctic temperatures even at low elevations sometime between the first of October and the middle of November, and more often there will be several lighter snow events as well. These are most common towards the end of autumn, of course, but they can happen at any time. I have seen temperatures fail to get out of the single digits on October 1, for example. Bring layers, warm gloves and hat, a winter survival kit for your vehicle, and waders and raingear without leaks!
Except immediately after storms, the water will be low and clear at this time. Even after storms, it is unusual for even mud-prone rivers like the Yellowstone to get dirty, since higher elevations usually see snow rather than rain in the fall, which knocks loose less sediment. The water will also be cold. No high-elevation (over about 6500 feet) waters save geothermally-heated rivers like the Firehole are worth fishing except during exceptional warm spells from now until June. The water is just too cold. Even on low-elevation and geothermal waters, the water will be cold enough that falling in can be hazardous, so have spare dry clothes available.
Without exception, the top fisheries in late fall are those that stay warm the longest and those that hold fall-run brown trout (and some rainbows). Most waters that fish well once October rolls around feature both factors.
Low-elevation rivers, whether freestone or tailwater, are the most productive fisheries in a general sense. These include all “big names:” The Yellowstone, Missouri, Madison, and Gallatin all fall into this category, as do most other famous rivers in Montana outside of my operations area. All large rivers in the area hold fall-run brown trout, and since they’re at lower elevations and bigger than other fisheries, they don’t get as cold as quickly and so also maintain insect hatches for at least part of this period, and often right until the end if the coldest weather holds off.
Geothermal waters and spring creeks are also good, since the warm(er) water inputs keep temperatures much more stable year-round. For dry fly fishing, check the Firehole or the Paradise Valley spring creeks, where this is prime BWO time. For bigger browns, the lower Gibbon, lower Firehole, lower Gardner, and Madison within Yellowstone Park are good through the first Sunday in November, while the spring creeks continue to fish well for them even into the winter.
Small ranch lakes are the other good option at this time, particularly during October. As the water temperatures begin to drop, the weeds that are so annoying in these lakes much of the season die back and the trout that live in these lakes (of whatever species) feed aggressively on leeches and other large fare in preparation for winter. Without exception, the top ten “big number” days my clients have had on these lakes have occurred in late fall.
Waters that are seldom worth fishing in late fall include all small streams except spring creeks as well as high-elevation rivers, including the Lamar System in Yellowstone Park. You will still see tons of people fishing this water at this time as long as the weather is tolerable, but they will seldom be doing any good. The Yellowstone inside Yellowstone Park is also questionable if the weather has been good, but if you want to catch cutthroats, it’s probably your best option.
My favorite waters to fish and guide in late fall are the lower Gardner River in Yellowstone Park, the Yellowstone River float stretches outside the Park, the “Land of Giants” stretch of the Missouri River (which is probably the warmest option), and private lakes.
Fly Fishing Montana in Late Fall: Tactics
On private lakes, fish leeches, streamers, San Juan Worms, and other large fare. Fish these flies relatively slowly, either using a slow strip retrieve or under an indicator. Ledges, the edges of weed beds, and wind-swept shorelines are good places to start.
On flowing waters, you basically have two options, both of which will work to a greater or lesser degree depending on the water in question, the weather, and your goals. The first option is matching the insects common in late fall both on the surface and subsurface. The second option is to target fall-run browns and the smaller number of fall-run rainbows that come with them, and in some cases the resident trout that gorge on insects and eggs kicked loose by the spawners, using nymphs and streamers.
The primary late fall insects on all waters are Blue-winged Olives, both Baetis and the tiny Pseudos, as well as midges, which at this time are usually dark in color with very pale gray wings. On geothermal waters, you will still see some blond White Miller caddis as well, though these peter out through late fall. When you don’t see fish rising, fish subsurface flies that match these insects. Look for walking-speed water that’s at least two or three feet deep everywhere except spring creeks and geothermal rivers like the Firehole. The fish may be in faster water on spring creeks, tailwaters, and geothermal rivers. Everywhere else they like it slow. Rising fish are most likely to be found in areas bugs collect: foam piles, eddies, and slow current seams. The colder the water, the more likely rising fish will concentrate on the side of the river receiving more sun, usually the east side since most of our waters run generally north. Rising trout are unlikely save between noon and 4:00PM, and I suggest fishing dries only when you see risers from now until late spring.
When targeting fall browns, fish deeper and/or more turbulent water to avoid harassing actively spawning fish. The full spawn begins around mid-October and continues through the middle of November or later. A good rule of thumb is to avoid fishing areas with gravel bottoms that are less than four or five feet deep, since such areas are prime spawning habitat. You will find plenty of fish staging downstream of these areas, either fish that have not started spawning yet or those that have finished (as well as resident fish eating the eggs of spawners).
Good flies for targeting these fish are egg patterns, stonefly and large attractor nymphs, and streamers and large steelhead-style wet flies. Nymphs and eggs will produce more fish. Streamers and large wet flies often produce bigger fish and harder strikes. The best areas are walking-speed runs with boulder-strewn bottoms that are at least waist-deep, with six or eight feet deep even better. You can also “intercept” fish by hitting the deepest, slowest areas within long runs of shallow, fast water, though these can be hard to pinpoint. On larger float rivers, either swing streamers on foot in the big runs or “strip and rip” them if you’re fishing from a moving boat. By late fall, you can fish for running browns and ‘bows all day regardless of weather, but the very best weather for targeting these trout is when it’s gray and spitting rain or snow. This also keeps crowds away. The crowds of anglers targeting these trout can be quite intense in some areas, particularly the Madison near Yellowstone’s west entrance and the Lewis River in the central part of Yellowstone Park.
Who Should Consider Fly Fishing Montana in Late Fall?
Late autumn is prime time for big fish fanatics who can tolerate cold and ugly weather. Early spring is probably just as productive for large fish (though not browns), but more waters are open and fishing well in late fall than spring, and water conditions seldom get muddy. Beginners need not apply. Neither should people who dislike fishing subsurface flies, since the dry fly bite in late fall is much less consistent than it is earlier in the season. This is also a poor time for anglers who like to use a wide range of tactics, since as noted above only a handful of techniques tend to produce. In addition, this is actually a poor time for anglers who like to hike to fish. There are plenty of options for walks of a half-mile or so to get away from the road, but besides the Lewis River, there are no hikes over about a mile that are likely to produce as well as options closer to the road.