St. Joe River Idaho Hatch Chart
Northern Idaho. One of the premier wild cutthroat streams in the West, draining the Bitterroot Range into Lake Coeur d'Alene. The upper St. Joe above Avery is roadless wild country — westslope cutthroat in cold, clear water. The lower river below Avery is more accessible and holds larger fish, including some bull trout.
The upper river is catch-and-release only for cutthroat. Check current Idaho Fish and Game regulations — rules vary significantly by section. Bull trout are catch-and-release only statewide.
Best fishing is June through September, with the salmonfly hatch in late June being the signature event. The upper river fishes well into September with hoppers and late-season olives. Snowpack drives timing — confirm flows before planning a trip to the upper canyon.
Shop by type: dry flies, nymphs, Euro nymphs, hoppers and terrestrials, streamers.
Year at a glance
| Month | Primary hatches | Also carry | Typical sizes |
|---|---|---|---|
| Jan | Midges | Small stonefly nymphs | 18-22 |
| Feb | Midges, BWO | Small stonefly nymphs | 16-22 |
| Mar | BWO, early Skwala | Midges | 14-20, Skwala 8-12 |
| Apr | BWO, Skwala, March Brown | Early caddis, runoff begins | 12-18 |
| May | Caddis, stonefly nymphs | BWO, high runoff typical | Caddis 14-16, stones 6-10 |
| Jun | Salmonfly, golden stone, caddis | PMD late month | Stones 4-10, caddis 14-16 |
| Jul | PMD, caddis, yellow sally | Golden stone fading, hoppers start | 14-18 |
| Aug | Hoppers, ants, caddis | Late PMD, beetles | Hopper 8-12, ant 14-16 |
| Sep | Hoppers, BWO, October caddis | Ants, streamers | 10-18, BWO 18-20 |
| Oct | October caddis, BWO | Midges | Caddis 8-12, BWO 18-22 |
| Nov | BWO, midges | Small streamers | 18-22 |
| Dec | Midges | Small nymphs | 18-22 |
January
Upper river is locked in snow. Lower river near St. Maries can fish on mild days with small flies and slow presentations.
- Midges - 18-22. Zebra midge or small Euro nymph in a two-fly rig.
- Small dark stonefly nymphs along the bottom.
February
Same program as January. Olives can show on overcast afternoons when temps nudge above freezing.
- Midges and BWO on gray days.
- Pheasant tail nymphs subsurface.
March
Olives pick up on the lower river. Skwala stoneflies begin on warmer stretches. The upper canyon is still inaccessible.
- BWO - 16-20. Dry and Barr's Baetis emerger.
- Skwala - 8-12. Rubber-leg nymph along banks, Stimulator-style dry on warm afternoons. See nymphs and dry flies.
April
Snowmelt begins pushing flows. Fish edges and any clear tributary water. The accessible lower river is the best bet.
- BWO and March Brown on cloudy days.
- Skwala still works on warming bank water.
- Early dark caddis.
May
High water month — the upper river is typically blown out through most of May. Caddis build on the lower river when flows allow. Stonefly nymphs are migrating.
- Caddis - 14-16. Elk hair caddis and the caddis assortment.
- Stonefly nymphs 6-10 from nymphs.
- BWO on gray afternoons when flows drop enough to fish.
June
The signature month on the St. Joe. Salmonflies hatch as flows drop — usually starting in the lower river in early June and moving upstream through the month. Upper canyon access opens as roads clear. Plan around the salmonfly migration for the best dry-fly opportunity of the year.
- Salmonfly - 4-8. A West Fork Salmonfly or large Stimulator against the bank. Fish the leading edge of the hatch.
- Golden stone - 6-10. Overlaps with and follows the salmonfly.
- Caddis - 14-16 in the evenings throughout the month.
- Late June: first PMD in riffles, 16-18.
July
Classic summer cutthroat fishing. PMDs in the morning, caddis in the evening, yellow sallies in fast riffles. The upper river is at its best. Cutthroat are aggressive and will take a well-presented dry.
- PMD - 16-18. Pale Morning Dun with a pheasant tail dropper.
- Yellow sally - 14-16 in fast pocket water.
- Caddis evenings. Elk hair.
- Early hoppers along grassy banks — hoppers and terrestrials.
August
Terrestrial season on the upper river. Cutthroat rise eagerly to hoppers, ants, and beetles. Fish early on the lower river — it warms by midday.
- Hoppers, ants, beetles - hoppers and terrestrials. A hopper-dropper with a small nymph underneath covers both feeding lanes.
- Evening caddis.
- Late PMD on cool mornings in the upper canyon.
September
One of the best months on the upper river. Crowds thin after Labor Day. Terrestrials still work. Olives return as nights cool. October caddis begin on the lower river.
- Hoppers and ants until the first hard frost.
- BWO - parachute BWO and the Baetis emerger, 18-20.
- Early October caddis - large orange dry, 8-12.
- Streamers in deeper slots at last light.
October
Fall colors in the canyon. October caddis and olives for willing cutthroat. Upper river access can close with early snow — check road conditions.
- October caddis and BWO.
- Midges in slow pools.
- Streamers for larger fish and bull trout water.
November
Lower river only. Short days, cold water. Small flies and slow drifts.
December
Midge and nymph program on accessible lower water. Most of the drainage is snow-covered.
- Zebra midge and small nymphs.
A western dry and nymph assortment covers the trout year. Add a salmonfly pattern, hoppers, and a few October caddis for the St. Joe's peak season.