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southwest montana hatches

Southwest Montana is world renowned for its major hatch events. From giant stoneflies to tiny tricos, there is a hatch to chase in every season. The dry fly possibilities are endless and big fish will come to the surface here. That’s a part of what makes fishing the local rivers so special. 

Winter and Spring Hatches

Dry fly fishing is less reliable during winter and spring but there are still some great days to be had. Midges and BWO’s are the primary insects during this time so bring your small fly A-game. Parachutes and cripples that sit low in the surface film are especially effective. 

Mother Day Caddis

May sees rising water but the mother’s day caddis also occurs, activating feeding frenzies even when the water is still off color. It’s hard to miss this hatch as clouds of caddis flutter on the water. Shake the bushes and you will see them swarm as well. The Beaverhead and Big Hole both have great caddis action and the flows are more stable than other local rivers. The upper Clark Fork is a caddis factory and the Yellowstone has a huge Mother’s Day caddis event when the river does not completely blow out. While this early season caddis hatch is spectacular, the bugs will continue throughout the entire summer, making for a reliable hatch opportunity to pursue.

Skwala Stoneflies

April is a big month for Skwala stoneflies, especially in the northwestern region but they show up in the southwest as well. The Bitterroot River, Clark Fork River, Missouri and many other local rivers will see these bugs filtering along the banks. Big fish often sit in slack water along the banks where they can discreetly suck down these stoneflies. If you don’t see risers, sticking to the dry fly can still produce some great fish.


This is the big one and it gets everyone excited. Salmonflies are huge and they arrive with the beginning of summer. It’s hard to dream up a better way to kick off the good weather than with a hatch of behemoth bugs. Only a few rivers see this hatch and they are popular during this season. The Madison is especially overrun with boats and anglers. The Big Hole has an epic salmonfly hatch and being a permitted river, the commercial boat traffic is controlled. Rock Creek is also permitted and has an incredible hatch. Both offer great fishing with the average size being bigger on the Big Hole.

Golden Stones and Yellow Sallies

As salmonflies disappear, golden stoneflies replace them and remain available throughout the summer. Goldens have a range of sizes with big size 8’s and small yellow sallies that are 14’s and 16’s. Start with the bigger sizes in late June and early July but drop down to smaller ones as the flows drop and the summer heat hits. Golden stones are one of the most reliable July Montana hatches.

Mayfly Hatches

A variety of mayfly species hatch throughout the year in southwestern Montana. PMD’s are important during summer and some fly patterns can imitate the mayfly and little yellow stoneflies at the same time. The early and late seasons see hatches of blue wing olives and the early summer produces gray drakes and brown drakes. Focus on matching the size and color with parachute style dry flies or use a searching pattern like the purple haze. 


The late summer and early fall bring on swarms of tricos. These tiny, black insects turn trout into selective feeders that sit back in slow moving flat water sections of the rivers. The bigger fish also love little tricos and that means you can