Yellowstone browns and rainbows shift toward streamer season

What's biting

What's next

Expect water temperatures to hold in the low to mid 40s, with the coldest water on the smaller gauge at 269 cfs. Flylords Mag suggests drifting streamers in early autumn, and that approach suits the steady flows we're seeing, since a big fly can swing or drift through the same lanes trout use to ambush baitfish.

On a New Moon, nights are dark and mornings tend to start slow. Plan around the warmest part of the afternoon, when water temperatures peak by a degree or two and fish are most willing to move. Gink and Gasoline (fly) stresses that nymph rigs often fail for lack of weight, so add split shot until your flies tick bottom in the slower, deeper runs where trout stack up as temperatures drop.

MidCurrent reports that midge and small nymph patterns fit low-light, overcast days, so keep a few in the box for cloudy afternoons.

Context

Mid-October on southwest Montana rivers is typically the transition from fall dry-fly and nymph fishing to streamer and egg-pattern fishing. Flows are usually near their annual low to moderate range after irrigation season ends, and cooling water tends to concentrate fish in deeper runs and tailouts. Brown trout are generally moving toward spawning mode at this time of year, so check state regulations for any seasonal closures or spawning-area protections before heading out.