San Juan River Fly Fishing Report - May 5/10/2026
San Juan River (New Mexico) Fly Fishing Report
Midges & BWOs Firing — Spring Tailwater Fishing at Its Best Below Navajo Dam
Report Date: May 10, 2026 | Next Update: May 17, 2026
Current River Conditions
The San Juan below Navajo Dam is fishing exceptionally well this spring, with flows in a comfortable wading range following a late-April spike. Midges and Blue-Winged Olives are the dominant hatches, and the entire Quality Waters section is producing consistent action throughout the day.
Flow & Clarity
Real-time gauge data unavailable. Recent guide reports indicate flows in the 450–650 CFS range with good clarity; dam releases from Navajo have been steady. Expect clear to slightly off-color conditions — flash in your patterns helps.
Real-time gauge data unavailable. Recent guide reports indicate flows in the 450–650 CFS range with good clarity; dam releases from Navajo have been steady. Expect clear to slightly off-color conditions — flash in your patterns helps.
Water Temperature
Real-time gauge data unavailable. Tailwater temps below Navajo Dam typically hold in the low-to-mid 40s°F in early May, warming slightly into the upper 40s°F by afternoon — ideal for active trout feeding.
Real-time gauge data unavailable. Tailwater temps below Navajo Dam typically hold in the low-to-mid 40s°F in early May, warming slightly into the upper 40s°F by afternoon — ideal for active trout feeding.
Weather
Weather data unavailable. Typical early May conditions in the San Juan basin bring cool mornings, afternoon warming, and possible spring winds. Cloudy afternoons favor extended BWO hatches. Dress in layers.
Weather data unavailable. Typical early May conditions in the San Juan basin bring cool mornings, afternoon warming, and possible spring winds. Cloudy afternoons favor extended BWO hatches. Dress in layers.
Access & Regs
Open year-round. Quality Waters section below Navajo Dam: artificial flies only, barbless hooks, single hook only — no tandem/dropper/multi-fly rigs. Harvest permitted per NM Game & Fish limits. Valid NM fishing license required.
Open year-round. Quality Waters section below Navajo Dam: artificial flies only, barbless hooks, single hook only — no tandem/dropper/multi-fly rigs. Harvest permitted per NM Game & Fish limits. Valid NM fishing license required.
Hatch Chart
| Insect | Size | Activity | Prime Time |
|---|---|---|---|
| Midges (Chironomidae) — Larvae/Pupa/Adult | #20–#24 | 🟢 Excellent — All Day | All day; peak 11:30 AM–2:00 PM |
| Blue-Winged Olive (Baetis) — Nymph & Dun | #20–#22 | 🟢 Strong — Afternoon | 1:00 PM–5:00 PM; best on overcast days |
| Midge Cluster — Adult | #20–#22 | 🟡 Moderate — Surface | Midday, especially in slower flats |
| San Juan Worm (annelid) | #12–#16 | 🟢 Reliable — Sub-surface | All day, especially after any flow bump |
| Scud | #12–#16 | 🟡 Moderate — Sub-surface | All day in moss beds and slower runs |
| Caddis (early season) | #14–#16 | 🔴 Sparse — Emerging | Late afternoon; picking up as temps rise |
Recommended Flies
- Black Zebra Midge (TBH) #20 — The San Juan's bread-and-butter midge pupa; dead-drift deep in riffles and runs all morning.
- Olsen's Peacock Blowtorch Barbless #22–#24 — Deadly midge/BWO crossover pattern; barbless and ready for the Quality Waters section.
- Olsen's Hare's Ear Blowtorch Barbless #20–#28 — Slim, flashy profile that trout key on during the mid-morning midge push.
- Juju Baetis Tungsten #22 — Gets down fast in the afternoon BWO window; olive and gray are the go-to colors.
- BWO WD-40 #22 — Classic Baetis emerger/nymph; fish it in the film or just below during the 1–5 PM hatch.
- Barr's Flashback Emerger BWO #22 — Excellent transitional pattern as BWOs begin to emerge in the surface film mid-afternoon.
- Parachute Blue Wing Olive #22 — Go-to dry when trout are visibly sipping duns; fish with a long, drag-free float on 7X tippet.
- Egan's CDC Rainbow Warrior #22 — Midge/Baetis hybrid that shines in the surface film; excellent visibility for the angler.
- Top Secret Baetis #16 — Proven San Juan attractor nymph; works well as a searching pattern between hatches.
- Tungsten Rainbow Warrior Pearl #22 — Flash and weight in one; excellent midge pupa imitation for deeper runs near the dam.
- Wiggly Worm (TBH) #8 — San Juan worm analog; fish it as your single fly on a tight-line rig when flows bump up.
- Tungsten Jig Bugger Olive Barbless #14 — Swing or strip through deeper runs and seams for the river's larger brown and rainbow trout.
- Lil Bit Craven Dark Olive #22 — Tiny, precise midge/Baetis pattern for picky risers in the flats; fish it on 7X with a perfect drift.
Tactics & Tips
Regulations first: The Quality Waters section below Navajo Dam requires artificial flies only, barbless hooks, and a single-hook-only rule — no tandem rigs, no dropper setups, no multi-fly configurations of any kind. Officers are actively checking; file those barbs or fish barbless patterns straight from the catalog. A valid New Mexico fishing license is required.
Morning (7 AM–11 AM): Start near the dam in the best midging water. Fish a single midge larva or pupa (Black Zebra Midge, Olsen's Blowtorch) on a tight-line or indicator rig, getting your fly deep in the riffles and runs. Olive, gray, black, and red/orange are the top midge colors. Use 6X–7X fluorocarbon tippet and keep your drifts drag-free.
Midday (11:30 AM–2 PM): The midge hatch peaks. Watch for fish rising in clusters — switch to a single midge cluster dry or the Egan's CDC Rainbow Warrior in the surface film. Trout will be inspecting carefully; a long leader and perfect presentation are non-negotiable.
Afternoon (1 PM–5 PM): The BWO hatch comes on, especially below Texas Hole on overcast days. Transition to Baetis nymphs (Juju Baetis, BWO WD-40) fished just sub-surface, then switch to the Parachute BWO dry when you see duns on the water. Cloudy skies extend this hatch well into evening.
Streamer/worm option: When the hatch is off or flows are elevated, a single Wiggly Worm or Tungsten Jig Bugger fished on a tight-line through deeper runs and seams can produce the biggest fish of the day. Strip or dead-drift — both work. Move around the Quality Waters section to find where the hatches are most concentrated, and always watch for spawning redds — give them a wide berth and never wade through them.
