Western Montana Fly Fishing Seasons
The fishing season of Western Montana begins in late March and runs through October, with the exception of a few weeks in May and June. For approximately 3-6 weeks, the season pauses to allow for snow melt run-off. Also of importance, each river will vary somewhat with regards to its major insect hatches. Having said that, generally speaking....
Spring Season: late March into May
Skwala Stonefly #8
Gray Drake #12, March Brown #14
Blue Winged Olive #16, #18, #20
When the water temperature rises to the low 40s - usually mid to late March - on the Bitterroot, the much anticipated Skwala Stonefly hatch commences the season. This hatch at this time of year often yields the largest Brown Trout numbers caught on dry flies each year.
The Skwala Stonefly was long overlooked by anglers as a significant hatch in this region until the 1980's. Now this hatch is considered the best time to get Browns over twenty inches on dry flies. In addition to the Skwala Stone, we have good hatches of Gray Drakes, Blue Winged Olives, and other mayflies to round out the menu. However, be advised that at this time of year fishing can be very weather dependant. A late season arctic blast could shut down the fishing or an early warm up could turn it on.
Late Spring / Summer Season: May through August
Golden Stonefly #6, #8, #10
Green Drake #10
Pale Morning Dun #14, #16
Hoppers and Terrestrials
This time of year is generally referred to as our Summer Season. It begins with the acclaimed Salmonfly hatch on the upper reaches of most rivers. The fishing during this hatch is very exciting and often described as fast and furious. Most rivers will run high and swift at the tail end of the runoff.
The Salmonfly hatch can produce some of the largest numbers of fish caught in any given day. Days have passed when over one hundred trout have been landed but the average catch is somewhere closer to forty.
The Salmonfly hatch is immediately followed by the Golden Stones and then the Green Drakes and the Pale Morning Duns. Toward the end of July, we start fishing more terrestrial patterns such as grasshoppers and various attractor patterns. August is primarily terrestrial patterns of all shapes and sizes as well as attractor dries with an occasional nymph dropper. Also in mid-August the Trico Mayfly Spinners start gathering and falling. This is a particularly neat event that produces some excellent yet difficult dry fly fishing. Long leaders, tiny flies, and lots of patience are the rule.
Late Summer / Fall Season: September through October
Hecuba (Fall Drake) #10
Mahogony Dun #12, #14
Blue Winged Olive #18, #20
Hoppers and Terrestrials
Ahhh... Autumn. The best time of year (in my opinion) to be in the Northern Rockies. The Summer heat has passed and the weather becomes very pleasant. With the cooler evenings and more rain showers at this time of year, the rivers produce a resurgence of mayfly activity, starting with my favorite hatch of the year, the Hecuba or Fall Drake Mayfly. This size #10 orangeish, tannish, olivey bug must taste particularly good because the trout love them.
During this hatch we not only see more trout rising to our dry flies but a significant number of larger trout as well. The Hecubas start first and then the Mahogony Duns and Blue Winged Olives again. Many days in the Fall see multiple hatches occur with fish rising for hours in the foam lines and pools to the aquatic insect matter on the surface of the water.
Late in the Fall Season as the weather turns even cooler, the Blue Winged Olives prevail. Even well into October, there can be excellent dry fly and streamer fishing for big Browns preparing to spawn.