Fall River (ID) Fly Hatch Chart

Fall River hatch chart providing fly subspecies, sizes and emergence dates for major mayfly, caddisfly, stonefly and midge hatches occurring annually on the Fall River in eastern Idaho.

fall river fly hatch chart

Fall river hatch chart with peak dates and fly sizes.

Hatch sizes and activity dates for Fall River hatches may fluctuate from year to year due to changes in water flows and weather conditions. For anglers fishing the Fall River, having a selection of fly patterns covering the major hatches is recommended.

Fly HatchSizeDate
Midge18 - 22Jan 1 - Apr 30; Sep 1 - Dec 31
Pale Morning Dun16 - 20June 1 - July 31
Green Drake10 - 14June 1 - July 31
Salmonfly4 - 6June 1 - July 31
Golden Stonefly8 - 12June 1 - July 31
Caddis14 - 16June 1 - Aug 31
Spruce Moth10 - 12July 1 - July 31
Terrestrials6 - 18July 1 - Oct 31
Trico18 - 22Aug 1 - Oct 31
Mohagany Dun16 - 18Sep 1 - Oct 31
Blue Winged Olive (Baetis)16 - 24Sep 1 - Nov 30
Fall (October) Caddis8 - 12Sep 1 - Nov 30

Fall River Fly Patterns

Fishing adult stonefly patterns and nymphing subsurface with patterns that match the hatch is your best bet for netting some decent size trout on Fall River.

Terrestrials, especially grasshopper or attractor patterns will hook some larger trout during the summer months and well into the fall.

One specific fly pattern anglers report having success with is a #8 Coffee Black Pat’s Rubber Legs on a dropper. A Pat’s Rubber legs is a great imitation for a stonefly nymph and stoneflies are one of the more prolific hatches on Fall River during the spring and summer.