Owyhee River Hatch Chart

Fly hatch chart for Owyhee River in western Idaho. Chart includes emergence dates and recommended fly sizes for the major mayfly, caddisfly, and stonefly hatches along the Owyhee River. Emergence and peak hatch dates may vary due to annual changes in water flows and weather conditions.

owyhee river fly hatch chart

Owyhee River flies have three life stages: Nymph (Larvae), Pupae/Emergence, and Adult. The hatch dates in the chart below represent expected emergence/hatch dates. Flies exist subsurface as nymphs prior to the hatch date. This provides anglers an excellent opportunity to target foraging trout using nymph patterns that match the upcoming hatch.

Fly HatchSizeDate
Midges18 - 24Jan 1 - Dec 31
BWO16 - 22Jan 15 - June 30; Sep 1 - Nov 31
March Browns12 - 14Mar 1 - Apr 15
Skwala Stonefly6 - 10Mar 15 - Apr 31
Caddis16 - 18Apr 1 - Aug 31
Little Black Caddis16 - 18Apr 15 - June 15
Little Brown Stonefly14 - 18May 1 - June 30
Yellow Sally14 - 16May 1 - June 30
PMD16 - 18May 1 - Aug 31
Spotted Sedge Caddis16 - 18May 1 - Aug 31
Green Sedge Caddis16 - 20May 1 - Aug 31
Callibaetis (Speckled Wing Quills)14 - 18May 1 - Sep 30
Golden Stonefly8 - 12June 1 - July 31
Trico20 - 24July 1 - Sep 30
Ants10 - 16July 1 - Oct 15
Hoppers4 - 10July 1 - Oct 15
Beetles10 - 16July 1 - Oct 31
Mahogany14 - 18Sep 1 - Nov 30
October Caddis6 -10Sep 15 - Oct 31
Winter Stonefly18 - 20Dec 1 - Jan 31

Major Fly Hatches on the Owyhee

The fly fishing season on Owyhee River gets started with the Skwala Stonefly and March Brown hatches in mid to late March. If you hit the Owyhee in early March you’ll notice Skwala nymphs up and down the banks. Fishing Skwala nymph imitation patterns prior to and during the main hatch will net you some nice size browns. Dry flies become productive once hatches are in full swing.

Blue-winged Olive (BWO) hatches hit full stride in April, but you’ll find a few early season BWO hatches in March. Nymphing with BWO imitations in mid to late March, just before the main hatches take place, is a great strategy for getting some good hookups subsurface. Anglers report that once adult Blue-winged Olive mayflies begin to emerge, browns will start feeding at the surface and will only take dry flies.

A few more important fly hatches to plan for include Pale Morning duns, callibaetis or Speckled Wing Quills, Spotted Sedge caddisflies, Green Sedge caddisfly, and midges. During the summer and fall months, all the way through September, grasshoppers and ants are abundant along the Owyhee’s banks. Having some good terrestrial patterns in you fly box is recommended for fishing the late summer months.

Some Good Fly Patterns

Here are a few tried and true fly patterns for fishing the Owyhee River. Most of these patterns will work throughout the season, but matching the hatch is going to be most effective.

Skwala Stonefly Nymphs

  • Girdle Bugs (#12-14)
  • Rubber Legs Stonefly Nymph (#12-14)
  • Bead Head Hare’s Ear Nymph (#12)
  • Prince Nymph (#12-14)

Skwala Dry Flies

  • CDC Skwala (#12)
  • Bullet Head Skwala (#12)
  • Stimulator Skwala

Blue-winged Olive Dry Flies

  • CDC BWO (#20-22)
  • BWO Cripple (#20)
  • BWO Stimulator (#12)

Midge Dry Flies

  • Griffith’s Gnat (#20-22)
  • Suspended Midge (#20-24)
  • Sparkle CDC (#22-24)

A few Zebra Midges (#20-22), Pheasant Tail Nymphs (#18-20), and Hot Spot Nymphs (#18-20) will round out an ideal selection of flys for fishing the Owyhee just about any time of year.

One of my favorite setups for fishing any of the trout rivers in the northwest. A dropper rig with a Skwala dry fly dropper and any one of the nymphs listed above for the dropper is a perfect combo for Owyhee trout. You can test a few different nymph droppers until you dial in what works.