Fall Brown Trout Window Opens on Yellowstone and Missouri Systems

What's biting

What's next

Expect water temperatures to keep sliding toward the mid 40s as nights lengthen, which tends to slow fish in the cold morning hours and concentrate the best action from late morning through mid afternoon. The warmer 52°F reading at gauge 06041500 suggests that stretch holds comfortable temperatures longest into the afternoon.

Flows look stable and fishable across all four gauges, with gauge 06043500 at 360 cfs and gauge 06043120 at 232 cfs offering the clearest, lowest water for sight-fishing. Flylords Mag describes a bright, clear day where anglers spotted a big brown cruising a feeding circle and landed it with a precise cast, which fits this kind of low, clear flow. Plan to scan the water before wading, as Gink and Gasoline (fly) advises, and look for dark shapes and subtle movement.

The First Quarter moon gives moderate light in the evening, so late-day streamer sessions are worth a push. Weather shifts are worth watching, since Flylords Mag reports a slight temperature drop and a little rain kept fish biting all day at a high alpine lake.

Context

Mid October is typically the back half of the fall streamer window in this part of Montana. Brown trout move toward spawning behavior as water cools, becoming more aggressive and more concentrated, while insect activity thins to small midges and the occasional late mayfly. Flows are usually near their annual lows by now, which is what the current gauge readings reflect. Conditions look on schedule for the season, with water temperatures well within the range where trout feed actively. Respect spawning closures and avoid wading across redds.