If you’re planning to hit the Boulder River soon, leave the heavy-handed casts at home. Right now, the river is running “low and gin clear“, according to Montana Angler in Bozeman, meaning the trout have their antenna up and are easily spooked.

Here is the quick breakdown of what to expect, what’s biting, and how to play it as of July 22, 2026:

Because the Boulder drains the highest mountains in the state, water temperatures are staying nice and chilly. However, the fish are playing hard to get. You’ll find plenty of trout hanging out in the tail-outs, but they are highly alert. When they get hungry, they’ll transition into the shallow riffles to feed.

• Down Low: The hopper action is finally starting to heat up.
• Up High: Look out for morning spruce moths and lingering green drakes.

The Forecast

• August: The floating window is slamming shut fast as water levels drop. According to Montana Angler, once the boats are docked, the river becomes highly wadeable—“if you like walking and climbing over Boulders.”
• September & Beyond: The upper-elevation chill will keep the resident trout happy late into the season.
• October Bonus: The game changes in the fall. The report notes that later in the autumn, “some browns move up from the Yellowstone to add some big fish to the mix.”

Bring your A-game presentation, prepare for some rock scrambling, and embrace the technical, clear-water challenge.

You can check out Montana Angler at 435 East Main Street in Bozeman.