October Fishing on the Madison River

October weather, stream flows, and summary

October fly fishing on the Madison River may be considered the shoulder season, but in this final month of the fishing calendar, dedicated anglers can enjoy dry fly fishing and fishing for aggressive brown trout. October is the month of Blue Winged Olives and big trout chasing streamers. Gone are the long, sunny days of summer and with them busy boat ramps and numbers-hungry anglers. October is a month on the Madison River for anglers who appreciate the process and the surroundings, as much as the result. 

October weather is varied—from days of bright sunshine and highs in the 70s to blizzards and highs in the teens. The law of averages abides and the average daily high temperature hovers around 60 degrees F. There is slightly more precipitation in October than September with an average of 1.1” and the possibility of snow increases substantially with a 1.9” on average. Quality fishing opportunities can occur in these variable weather conditions, but in October often the lousiest weather produces the best fishing. 

Stream flows are consistent and clear on both major sections of the river. The Lower Madison—the river downstream of Ennis Lake and Madison Dam in the Beartrap Canyon, and the Upper Madison experience similar habits and hatches in October. The Upper Madison features exciting runs of lake-dwelling trout that the Lower Madison does not. Anglers desiring a shot at a trophy sized trout should target these sections of the Madison River. For more information read our blog post on Fall Run Browns on the Madison River.

For many anglers October and the regular occurrence of fall-like weather means a commitment to fishing streamers for aggressive brown trout. The Madison River in October is exactly that—a river ideally primed for targeting large trout with large flies. This is the month streamer addicts relish in the tug as the drug. 

But streamer fishing isn’t the only game on the Madison in October. Blue Winged Olives (BWOs) are the primary hatch of October. A few October caddis are spotted but they are not consistent and emerge in small numbers, usually one or two at a time compared to the thousands of insects during a BWO hatch. 

Planning to fish an October caddis hatch is more speculative than expectation. October does see a few days of sunshine and warm air temperatures above 65 degrees F, if this does happen terrestrials can become active for a brief timeframe.

October fishing: what to expect

Fly fishing the Madison in October is best enjoyed with the correct attitude. Because the weather can vary from day to day or hour to hour and the hatches can be sparse to thick and the brown trout can be on the chase or not, October on the Madison River is as much a process as it is producing pleasure. 

Sun, rain, and snow can all happen on the same day. And many days the worst weather creates the best fishing conditions. Blue Winged Olives tend to hatch in rainy or snow weather. Brown trout, especially large brown trout, are inherently more sensitive to bright sunshine in the fall. Fishing in cold, rainy, or snowy weather may not be what you find as enjoyable but armed with quality gear and a good attitude it just might pay dividends. 

A typical day fly fishing the Madison River in October begins at a reasonable hour. The need for an early start is gone because if Blue Winged Olives hatch they will begin around mid-morning or late afternoon. Large brown trout may be active early, but the sun rises between 7 and 8 AM most mornings in October so early starts are not crucial. Tandem two-fly nymph rigs still catch most fish in October, but this is the month for the streamer angler. 

Olive, black or brown streamers are the go-to choices for October trophy-sized trout. Favorite tactics include dead-drifting a large streamer below a strike indicator or dragging a large streamer off the bank. Many anglers will also trail a smaller nymph such as a size 16 or 18 mayfly nymph, creating a two-fly rig designed to entice a big brown trout or catch a selective rainbow or brown trout.

Dry fly anglers can also delight as hatches of Blue Winged Olives are a common occurrence. Both the Lower Madison and Upper Madison are known for strong emergence of these small mayflies. When conditions line-up appropriately, typically a forecast for light rain or snow flurries coupled with low winds, the slower currents of the Lower Madison are the perfect habitat for fishing these small mayflies. 

Where to find October trout on the Madison

Similar to September, trout on the Madison in October can be found in a variety of locations. Nymphs—mayfly, caddis, and stoneflies—are active in the Madison River year-round. Trout are most likely to be found in subsurface holding lies. 

For the fall run of lake-dwelling trout that venture out of Ennis, Quake, or Hebgen Lakes, target the deepest portions of slow runs or pools. For more information on these unique opportunities read our blog post on Fall Run Browns on the Madison River.

When fishing tandem nymph rigs, focus on the deeper water near shallow water, behind or in front of structure, or any place that can provide cover from predators or fast currents. If the sunshine pops and the air temperature hovers near 60 degrees F or higher, consider fishing terrestrials. Trout will expend vital energy and take the risk from deep cover because a morsel as large as a grasshopper, ant, or beetle may not pass by again that day. Fishing grasshoppers in October is a rarity but it does happen. 

As the month grows, hatches of BWO mayflies can increase and brown trout grow even more aggressive prior to fall spawning. BWO nymphs can be found throughout the river. When a strong hatch occurs, look for trout in slower currents and “softer water” such as the inside of river bends, seams behind rocks, and slower runs below riffles. 

Brown trout can be found in the usual predator hangouts—deeper water near shallow water, hiding near structure, or along a cut bank. Many brown trout will begin to spawn in October. These spawning fish may be found on their redds on shallow gravel bars. Please avoid targeting spawning trout when they are encountered.

Important October hatches

October hatches on the Madison River are relatively small compared to other months. The Madison River is home to a healthy population of stoneflies, mayflies, and caddis whose nymphs are active year-round, so even if the insects are not hatching, the nymphs are available to trout. 

The main hatch of October is the emergence of Blue Winged Olives. These small mayflies can hatch on any day during October. Overcast, rainy or snowy days see the strongest emergences. These mayflies are slightly smaller than their spring season cousins. Ranging in size from 16 to 22, these insects will emerge by late-morning or early afternoon and provide a few to several hours of dry fly fishing opportunities.

October caddis also hatch on the Madison River. These bugs may be large in size—about size 8—but their hatch is sporadic. In a day of angling only a few October caddis may actually be seen fluttering in the air but committing to a large dry fly can bring the occasional opportunistic trout to the surface. 

Madison River fly box for October

BWO dry flies sizes 16 to 22

BWO emergers sizes 16 to 20

BWO nymphs sizes 16 to 20

October caddis size 8

Crayfish patterns sizes 2 to 8

Sculpin patterns sizes 2 to 6

Streamers in olive, black or brown sizes 2 to 6