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 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 Hatch | Size | Date |
|---|---|---|
| Midges | 18 - 24 | Jan 1 - Dec 31 |
| BWO | 16 - 22 | Jan 15 - June 30; Sep 1 - Nov 31 |
| March Browns | 12 - 14 | Mar 1 - Apr 15 |
| Skwala Stonefly | 6 - 10 | Mar 15 - Apr 31 |
| Caddis | 16 - 18 | Apr 1 - Aug 31 |
| Little Black Caddis | 16 - 18 | Apr 15 - June 15 |
| Little Brown Stonefly | 14 - 18 | May 1 - June 30 |
| Yellow Sally | 14 - 16 | May 1 - June 30 |
| PMD | 16 - 18 | May 1 - Aug 31 |
| Spotted Sedge Caddis | 16 - 18 | May 1 - Aug 31 |
| Green Sedge Caddis | 16 - 20 | May 1 - Aug 31 |
| Callibaetis (Speckled Wing Quills) | 14 - 18 | May 1 - Sep 30 |
| Golden Stonefly | 8 - 12 | June 1 - July 31 |
| Trico | 20 - 24 | July 1 - Sep 30 |
| Ants | 10 - 16 | July 1 - Oct 15 |
| Hoppers | 4 - 10 | July 1 - Oct 15 |
| Beetles | 10 - 16 | July 1 - Oct 31 |
| Mahogany | 14 - 18 | Sep 1 - Nov 30 |
| October Caddis | 6 -10 | Sep 15 - Oct 31 |
| Winter Stonefly | 18 - 20 | Dec 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.
