Yellowstone and Missouri trout settle into fall pattern

What's biting

What's next

Expect steady, cool-water conditions over the next few days, with flows holding near current levels unless a weather system moves through. Readings in the high 40s to around 50°F keep trout feeding through the middle of the day, so the best window is likely late morning through mid-afternoon, when the water has had time to warm a degree or two.

Field & Stream points to blue-winged olives as the dominant fall mayfly hatch, matched with parachutes and Compara-duns on low, clear water. On the days a front moves in, it suggests switching to nymphs or big orange caddis patterns. Anglers should be ready to rotate between small dries in the afternoon and streamers or nymphs when the sky turns grey.

MT FWP Fishing News reports that some spawning closures on rivers began October 1, and that it lifted the Section 5 closure on the Big Hole River after rain improved flows. Check current Montana regulations and closure notices before choosing a stretch, since fall Brown Trout are on the move.

Context

Mid-October is late fall for this part of Montana, the point where trout feeding shifts from insect hatches toward calorie-heavy meals ahead of winter. Water in the high 40s is typical for the season and a sign the system has fully cooled from summer. Brown Trout spawning activity typically picks up around this time, so give redds a wide berth and avoid wading through gravel beds.