It’s early autumn here in Yellowstone Country, and we’ve enjoyed some beautiful weather this week. But our first true taste of scuzzy fall conditions is set to arrive today and stick around through the weekend. Cool, cloudy weather should jump-start fall hatches of Baetis and drake mayflies, while also encouraging migratory fish to get on the move.

Just as quickly as the weather rolls in, it looks like it will clear out by the start of next week, bringing a return to bright blue skies and warmer afternoons. Stay flexible this week, adjust your plans to the conditions, and enjoy a little bit of everything Yellowstone Country weather has to offer in September.

HERE'S THIS WEEK'S STANDOUTS. 

FIREHOLE RIVER

Cool, cloudy afternoons should bring some of the first consistent Baetis fishing of the fall to the Firehole. Look for these small, size #20-22 mayflies to emerge best when the weather is at its worst.

When the sun returns, don’t expect the same level of mayfly activity. Instead, throw a hopper along grassy, undercut banks, or turn your attention back to the Northeast Corner cutthroat streams. September is all about matching your plans to the conditions, and the Firehole is at its best right now when the weather turns cool, gray, and scuzzy.

MADISON RIVER

This is also a great week to connect with one of the season’s early lake-run browns or rainbows making their way upstream from Hebgen Lake into the Madison River in the Park. These large, migratory fish take advantage of periods of low light to move from the security of the deep lake into the shallow river, and we hope to see a fresh push of fish enter the system with the upcoming cool, cloudy weather. It’s still early in the run, but there are already some great fish scattered throughout the system.

GALLATIN RIVER

Look for a shift from terrestrials to fall Baetis hatches on the Gallatin in the Park this weekend. Cool, cloudy weather should provide ideal conditions for these small mayflies, with the afternoon hours being the best time to find rising fish. 

As always, the Gallatin is a consistent bet for nymph fishing when there isn’t much happening on the surface. Dry-dropper and indicator rigs are both effective ways to work the river’s deeper runs, riffles, and pocket water. Streamers will also become more of a go-to as fall progresses, especially on cool, overcast days when larger browns become increasingly aggressive.

SLOUGH CREEK

Fall hatches of Baetis, Heptagenia, and Hecuba mayflies continue on Slough Creek, and this week’s scuzzy weather should promote some good emergences. Cloud cover will make sight-fishing more difficult at times, but an increased number of bugs on the water should help pinpoint rising cutthroats. The best activity will likely come during the afternoon hours, when water temperatures warm slightly, and mayfly activity picks up.

LAMAR RIVER

Water conditions are in good shape in the Lamar Valley. Keep an eye on the forecast this weekend. If any significant rain develops out of this weekend's storm, we may see some cloudy water return. You can check the flows HERE and call the shop (406-646-7801) for current conditions. Ants, small hoppers, and Hecuba mayflies (size #12) will be at the top of the rotation here as well.