The Boulder has started it's runoff season and will need a few weeks before it clears up enough to fish.
The Month Ahead:
The Boulder runs off a bit later than the Yellowstone because of the high elevation snowpack. Run off will continue until late June but if flows are stable or dropping good fishing can be had. Trout will be in the softer protected water until things calm down so don’t fish the main current.
Long Term Fishing Forecast:
The Boulder will become a good option after runoff in the summer months. The colder water also makes it a nice option later in the summer when other fisheries are getting warm.