May Missouri River Fly Fishing Report 

May on the Missouri River has delivered a true spring spectacle. With flows around 4,500 CFS and water temperature hovering around 50°F, the river is in great shape despite the steady rain that’s been falling across the region. The extra moisture has really helped things green up and will help to fill our reservoirs.

May Out Flows From Holter Dam

Currently 4,500 CFS and rising out of Holter Dam. You can still walk and wade through plenty of water, especially in the side channels and along the gravel bars near Craig and Mid-Canon. Expect those flows to bump up a bit more with this week’s rain and as the mountains give up their snowpack in the coming weeks. Keep an eye on Dearborn and Little Prickly Pear if you’re floating below those junctions.

May Bug Life on the Missouri River

The dry fly is the headline this month. If you’re looking for targets, you’ll find them in the afternoon — especially during overcast days. From Wolf Creek down to Cascade.

Blue-Winged Olives (BWO) have taken center stage. Noses up in the slicks, and pods of trout sipping in the swirlies especially when we have the clouds to set the mood. Dry fly purists are finding success with the 401K Baetis, trusty rusty and Para Adams. Longer leaders and stealthy approaches are a must. It’s that time of year where good casts and better drifts get rewarded.

Caddis are starting to pop in the lower reaches—from Craig on down. These bugs are right on schedule thanks to the steady water temps, and a few fish are already looking up for them, particularly in the late afternoon. The Corn-Fed Caddis in a size 16 has been doing the trick.

Nymphing remains productive throughout the day. Sowbug, scuds, worms, perdigons and small Pheasant tail variations are a good call out of the gate. Once the bugs get going we have been shortening up and targeting the seams, slicks and shallow flats.

Streamer fishing has been fair and honestly we have not committed to it.  Smaller patterns like Kreelex, Sparkle Minnows, and the thin mint have moved fish along the banks and around mid-river structure. A slow retrieve with the occasional twitch seems to be the right speed right now.

What to Expect Going Forward

The second half of May should bring rising flows and more caddis. Keep an eye on river flow  — if the river jumps, the bite might slow as fish readjust, but overall May is a month of positive momentum. Warmer nights, stable water temps, and a healthy mix of hatches make for some great  fishing. The river is healthy, the bugs are here. Just be prepared for spring weather.