Best Flies For October Fishing In Montana

How can you tell a Halloween costume has been designed in Montana? It has snow pants! That’s the way October fly fishing in Missoula is going to end. But it sure doesn’t start that way! The Fishing and hatches can be incredible. Let’s take a look at some of the best flies for Montana in October.

October Caddis

October’s most well known bug is the October Caddis. Makes sense, right? This is a big caddis, size 8-10, and very difficult to miss on the water. As with so many other fall flies, like the Hecuba, it’s orange in color, and is best imitated with an Orange Elk Hair Caddis or an Orange Stimulator.  If you don’t have an October Caddis with you, a large Brindle Chute will work as well. If you see one October Caddis on the water, tie one on. The fish will be looking for them, even if there’s not a full-blown hatch. It’s a bit like Hopper fishing- throw to the likely water and be ready for the rise!

The more productive way to fish the October Caddis is subsurface, because it’s rare to come across a full hatch of these bugs. The big pupa are moving, and easy meals for trout looking to fatten up for the winter. The Bird of Prey, Red Fox Squirrel Nymph and the Orange Mop Fly are all very effective as a dropper or on a double nymph rig. Big and orange is the key to getting the trout’s attention. We recommend fluorocarbon leader when fall nymphing- the water is low and clear.


You have the chance of running into three or four different mayfly hatches in the month of October- Tricos, Hecubas, Blue Winged Olives and Mahoganies. The tricos are waning, but on warm, sunny days you will often find a spinner fall in the early afternoon. This can be a bit tricky, as the BWO’s will often be hatching at the same time. If you’ve made good presentations to a fish with a Blue Wing, and you’re not getting any eats, try Ron’s Trico Spinnner or a Hi-Viz Trico Spinner. It’s not fool proof, but it’s a good option if the BWO isn’t working.

The BWO is a very strong hatch in October, especially on the colder, cloudy days. BWO’s are not a single species- there are many types of Baetis that hatch at this time. Luckily, they are all imitated by the same bugs. On the surface, be ready with a Tilt Wing BWO, Split Flag BWO or a Swishers Clumpa. These three flies cover adults, emergers and cripples quite well. The BWO is a tiny fly in October, and is best imitated with an 18 or 20, so have a light leader ready. There is also a BWO coming off in October that is very gray in color, so have a few small Parachute Adams or Purple Hazes in your kit to cover that hatch.

If you choose to go subsurface for the BWO’s, have some SR Bullet Jigs in Olive to get deep. If the fish are near the surface, but not taking the insects off the surface, and unweighted Pheasant Tail is an excellent pattern for “smutting” fish. Drop it about 4’ off a dry fly (don’t worry if the dry sinks, it’s just an indicator at this point) and send it over the fish. The short dropper length will keep it near the surface, but not on the surface- just where the fish are taking the emerger.

The Mahogany is also a very strong hatch for fly fishing Missoula in October. Once established, they come off like clockwork starting at 1:00 in the afternoon, and will continue until the water temps get too cold. The Mahogany Thorax is very good for this hatch, as is the Tiltwing Mahogany. If you’re going subsurface, a Caramel Specialist Jig or Solitude Pheasant Tail jig will take fish all day.

The Mahogany’s will hatch in sun or clouds, though of course cloudy days are better. Again, the water is low and clear, so a longer, finer leader is called for. Think about some TroutHunter tippet in half sizes (4.5X, 5.5X) to get a little more stealth and a better drift. The Mahoganies are a size 14 at the beginning of the hatch, but as October ends, they will be as small as a 16, so have those sizes with you in nymphs and dries when you hit the water.

There’s an off chance you’ll see a Hecuba hatch as long as temps stay mild. You won’t miss it if it comes off, as the bugs are about a size 8! Have a Hecuba Cripple or a Brindle Chute with you, but don’t pin your hopes on this hatch- it can be very unpredictable. It’s much more apt to occur earlier in October, so have the flies with you, but don’t expect much.


The hoppers are still a bit of a presence in October, but no where near as important as they were in late August and September. The cold nights and rainy October weather is taking its toll on the hopper population, but if it gets hot and sunny enough that you hear them buzzing on the shore, then they’re in play for the fish! As always, a bit of a breeze helps the hopper fishing, but if you decide to run a hopper, drop an SR Bullet Olive or a Solitude Pheasant Tail jig off the back to make yourself a more effective angler.


Fly fishing Missoula in October can be one of the best times for streamers all year. The cold nights and shorter days tell the trout winter is coming, and it’s time to get some calories inside for the long winter months. While this blog writer tends to favor smaller streamers in fall like the Baby Swimcoach, due to the fact I’m heading out to match hatches, and need streamers that can be thrown on a 4-5 weight rod. In October, you can plan an entire day around streamer fishing.

The Blackfoot River is the first river to “turn off” due to the colder weather. It’s our northernmost river, and comes from the high mountains. It will get cold fast. But if you get out there in the first couple weeks of October, the streamer fishing can be extremely productive. Run the big flies like the Sex Dungeon or Mongrel Meat. Bang the banks, and start them as shallow as you dare. The fish are piled up behind boulders and off shelves, and are looking for a big meal before winter.

Rock Creek also has excellent streamer fishing in October. A Sparkle Minnow Sculpin is still a great producer up there at this time of year. Be ready for strikes in the middle of the river, where the bigger fish are. A wading staff is not remiss on Rock Creek at this point- those rocks can get very slippery this time of year, and if you’re trying to cover a lot of water with a streamer, good footing is paramount.

Final Thoughts

October is a month of big weather changes in Missoula. It starts off like the end of summer, and ends up like the beginning of winter. This means being prepared for the weather when you go to the water. Extra layers and a raincoat are critical. Put a spare set of clothes in the car, and leave them there. If you fall in in August, you’re just annoyed. If you fall kin on a cold, rainy day in October, it can turn into more of a problem. Having dry clothes to change into can be a game changer if the weather is cold and you’re soaking wet.

October in Missoula can be some of the best and most peaceful fishing of the year. The cold nights are slowing things down in the morning, so showing up about 9:30 is not a problem. And by 5:00, when the day starts to get chilly, it’s OK to head home to a warm dinner and a cold beverage! We like to call it Gentleman’s Fishing. No longer do you need to be on the water at dawn, and stay until after nightfall. The fishing will be best in the heat of the day, so why work the edges. Sleep in, enjoy, and get out when the day is nice. You’ll find it easy and more productive, which is what October fly fishing in Missoula is all about. 

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Missoula Fall Fly Fishing

As the fly fishing season transitions to fall and leaves turn from green to blazing, your approach to fly fishing needs to turn as well. Conditions are about to change around Missoula, and you’ll need to be aware. In mid-August, during the intense summer heat, the best fishing is early morning and then again in the evening. During the heat of the day, between noon and 7:00 pm, little action is seen. Hot temps and high sky drive trout deep to find shelter. Not the best time to fish. When the weather is hot, fishing is better near the edges of the day, and the hotter it gets, the closer to dawn and dusk you need to fish.

But the weather is changing during October and Novemeber, and so are the trout’s habits. Missoula is about to get colder and cloudy, and trout love that.

Trout want exactly what we want from the weather, a comfortable temperature. Not freezing, and not scorching hot. As fall approaches the Clark Fork River valley, those comfortable temps are moving from the edges of the day to the middle of the day. Those cool air temps and colder nights also lower the water temperatures. Trout are finding their comfort level in the middle of the day, instead of the edges of the day. As an angler, you should be as well!

Streamer fishing for Trout and Pike can be great in October and November.

Trout location also changes with water temperature. Warm water holds less oxygen, and high heat requires trout to find highly oxygenated water. As fall arrives, water temps fall and starts to hold more O2. Additionally, trout are cold blooded. Their metabolism slows as water temps fall. These two variables combine to change the trout’s holding lies. Trout use less energy, need less energy and now have highly oxygenated water. Cold weather moves trout to slower moving, softer water. Combine slow metabolism and high O2 content, and trout can and will move into water they shun in high summer. In short, late season fly fishing can be summed up this way, you’re going to find fish feeding in the middle of the day in softer, slower water.

Dropping water temps make fall streamer fishing some of the best of the year. The Brown Trout are moving upriver to spawn, and colder water temperatures let trout know they need to grab as many calories as they can get. A streamer in the morning, before the hatches start, can be a deadly tactic. Make sure to size your streamer to your fly line weight. Traditionally, fall streamers have some yellow or orange in them, though Brown Trout will move for a white streamer at almost any time. Depending on river choice, a sink tip may or may not be in order. The Blackfoot River and Clark Fork River always have sink tip water, while the parts of the Bitterroot River and Rock Creek may not be perfect for sink tip streamer fishing. In all the local Missoula rivers, big fish are moving for streamers! (Click here for 13 tips for fishing streamers)

In Missoula Montana, fall means a lot of other things to its residents. There are two distinct seasons that arrive with the cool weather, hunting season and Griz season. The University of Montana fields a very competitive football team, and Washington Grizzly stadium holds 26,000 rabid fans every Saturday when the Griz are home. From the angler’s standpoint, you know where 26,000 of your closest friends will be from 10:00 am to 5:00 pm. Not a bad time to go fishing!

A wide angle shot of the Griz football team taking on an opponent inside Washington Grizzly.

Other residents live here for the hunting. Antelope, deer, elk, Bear, Turkey, Pheasants and Waterfowl are all calling to the sportsmen of Montana. With such a limited season in the woods, most angling hunters put down their rods to pick up bows and rifles, and they head to the mountains. For those who angle, that means another large segment of friends are off the rivers as well. The crowds we’ve experienced throughout the summer are clearing out for football and hunting. Just like the grasshopper population is knocked down by fall’s cold weather, the fishermen population is knocked way down by fall’s cold weather activities. The rivers open up in the fall.

There are other issues that come up in fall fishing. As this is being written, there is a cold front coming in, bringing some winter weather. Water and cold weather are not a good combo. Hypothermia is a real concern, whether from falling in or just extended wading. We all know the fastest way to chill beer is put it in an ice bath. When you’re wading, especially as the water temps cool, you’re just like that beer, walking in a cold water bath. That drains energy and heat. Late season fishing means you need to plan ahead a bit. Have a spare change of clothes in the rig. Doesn’t need to be a tuxedo, just dry! Extra food and some water doesn’t hurt either. Maybe a thermos of hot coffee or soup. You get the point. Fall in August, and your friends laugh. Fall in on a 40 degree day, and it’s a bit more serious.

Missoula fly fishing guides and fisherman look forward to the amazing hatches and streamer fishing that the Fall has to offer. The seasons are turning, and long winter is just around the corner. But before the cold gets here to stay, the cool weather will make the fishing something wondrous to behold. Streamers move the big fish, hatches Like BWO, Mahogany and October Caddis bring the anglers out for one last hurrah. To many in town, fall fishing is the pinnacle of the entire year.