March is a transition month on the Bighorn — and one of our favorites. You can feel the river shifting gears. Water temperatures are climbing through the mid-30s into the low 40s, trout are becoming more active, and the Blue Winged Olive hatch is beginning to show on overcast afternoons.
Spring runoff is beginning to influence the system in places — water remains cold and trout are keyed to subsurface food. Focus on deep nymphing, midge and BWO presentations, and slow streamer work near structure.
Sowbugs and scuds have been very effective and should continue producing into spring. A mayfly nymph paired with your sowbug has been a deadly nymph rig. Streamer fishing has been surprisingly decent, with both flashy and natural patterns producing.
What's Working — March
Nymphs: Sowbug #16, Scud #16, Zebra Midge #18-20, Pheasant Tail #16-18, Pink and Purple Perdigons — keep everything deep and drifting clean
Dries: CDC Baetis #18 on calm overcast afternoons — watch for subtle rises in softer water
Streamers: Olive Woolly Bugger #6, Thin Mint — slow and deliberate near structure and undercut banks
Target: Softer runs and deeper buckets — mid-morning to afternoon is prime as slight afternoon warming kicks off hatch activity
April is just around the corner and the BWO hatch will be firing by the time you read this. The Bighorn is waking up.
A Note on Licenses
Effective March 1, 2026, Montana Fish, Wildlife & Parks no longer allows fly shops to sell fishing licenses on-site. Purchase your license online before arriving in Fort Smith.