Boulder River Fly Fishing in September
As with August, early September is a tough month for fishing on the Boulder River. Low, warm water creates a stressful environment for the trout. When cool-weather and shorter nights arrive in mid-September, fishing conditions start to improve, but irrigation demands continue to keep flows very low, historically, through late September.
By the end of the month, when the water cools down and recreational traffic diminishes, adventurous anglers can find solitude and rewarding days along the upper river and near the Boulder Forks FAS.
Boulder River Fly Fishing Hatches in September
Terrestrial insects such as grasshoppers, ants, and beetles continue to be the mainstays in September.
The arrival of cool air and cloudy weather reignites mayfly activity. Blue-winged olives (BWO) and western red quills are common on overcast days along the lower river.
Beetle patterns become most effective in mid-September. Fish these on long leaders along the seams next to mid-river boulders. We prefer to fish a small, single dry like the Hi-Viz Foam Beetle on 5x tippet. Look for trout sitting in the eddies behind boulders.
Boulder River Fly Fishing Techniques in September
Low, clear water calls for stealthy approaches and accurate fly presentations in early fall. Overcast conditions can spark mayfly hatches and bring trout to the surface. Dry fly fishing is the mainstay for wary, shallow water trout during this time of the year.
In the deeper pools near Big Timber and 8-Mile Bridge, however, nymph fishing with 9-foot, 5X leaders becomes productive again, as fish start to migrate back toward their colder water haunts.
Our Bozeman fly fishing guides use tandem nymph rigs with two small flies in these deeper sections. Attach a strike indicator about 4-feet above the first fly and add weight as needed. We prefer sparse patterns in dark colors to imitate the most active aquatic insects like midges and BWO nymphs.
Bozeman Fly Fishing Guide Pro Tip:
Beetle patterns become most effective in mid-September, fish these on long leaders to help perfect a drag-free drift along the seams next to mid-river boulders. We prefer to fish a small, single dry like the Hi-Viz Foam Beetle on 5x tippet when we can spot feeding trout sitting in the eddies behind a rock or boulder.
Boulder River Fly Box for September
Boulder River Fly Fishing Trips in September
Boulder River levels are historically very low through September until local irrigators reduce their demands. Cooling temperatures and shortening days quickly reinvigorate the trout in the river. Low flows make angling conditions challenging and floating in rafts nearly impossible.
Our Bozeman fly fishing guides focus their efforts on the larger Montana rivers near Bozeman in September, including Yellowstone, Madison, Gallatin, and Jefferson.
Overcast conditions and cooing water ignite blanket hatches of BWO and Pseudocleon mayflies. Brown trout start to migrate throughout the river drainages, becoming increasingly aggressive as their fall spawning season approaches. There are many great fly fishing options near Bozeman in September on the larger mainstem rivers.
Fins and Feathers Guide Service has been outfitting Montana fly fishing day trips near Bozeman—and across the Treasure State—for over 23 years. Our talented team of patient, expert Montana fly fishing guides welcomes anglers with all skill levels and tailors each day to your interests. Reservations can be secured online, via e-mail, or over the phone by calling us at 1-406-468-5019.