The Yellowstone has still been producing solid results but has come back to earth a bit, but with the heat things are slowing down in the afternoon. The hopper bite is just starting and should improve in the coming weeks. The best fishing is still early in the morning. Hot days have pushed trout into the fast water so avoid the long frog water slicks right now and look for the riffles. There are still some nocturnal stones down low and dry fly fishing is good at dawn down there with rubber legs underneath producing some fish. There is some algae drifting on the lower river but it is still fishable. Nymphing tight bankside structure has been quite good but the trout are moving to riffles and runs. Streamer fishing has also been very, very good during low light levels as is nymphing large stonefly patterns and sculpins trailed by basic bead head nymphs. In addition to the salmonflies, we have been seeing caddis and yellow sallies. Nymphing has been red hot. A nymph rig sporting a mega prince, pat's rubberlegs, FKA prince or a lil' spanker should get the job done. Target slower banks, inside bends, spillovers, and all "walking speed" water. Fishing a flutter bug, water walker, foam run caddis, or a small stimulator should get you a handful of eats on the surface.
Best Flies for the Yellowstone River Right Now:
Mega Prince #8-12
Pat's rubberlegs #8-12
FKA prince #12-16
Foam run caddis #12-16
Flutter bug #6-8
The Month Ahead:
The current conditions will hold out for another week or so. Trout will transition more to terrestrials on the surface and the standard nymphing patterns will hold out underneath. The most important factor is time of day and water temps. If hot days persist get up early and fish the fast water.
Long Term Fishing Forecast:
The Yellowstone should be a great option in the fall. As temperatures drop trout will move back into the slower slicks, eddies and glides and the small mayfly fishing will improve over baetis and the random drakes. October fishing is always solid on the stone to aggressive browns.