Free Resource · Updated 2026
Month-by-month hatch timing, fly pattern recommendations, and current conditions for the San Juan River in 2026. New Mexico's most celebrated tailwater runs cold and clear below Navajo Dam, with year-round midge hatches and strong PMD and BWO action through spring and fall.
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San Juan River Hatch Calendar at a Glance
The San Juan River below Navajo Dam in northwest New Mexico is one of the premier tailwaters in the country. The quality water section runs roughly three and a half miles from the dam to Texas Hole. Cold releases from the bottom of Navajo Reservoir keep water temps stable year-round, usually in the low 40s to low 50s. The river is wide, clear, and flat in most places, with good wading on gravel and sand.
The San Juan is a midge fishery first. Midges are active every month of the year, with the densest hatches in winter and early spring. Fish here are used to pressure and can be selective. Small patterns in sizes 22 to 26 and light tippet are standard. The Zebra Midge, RS2, and Griffith's Gnat cover most midge situations throughout the season.
Spring and fall BWO hatches are the other signature events on the San Juan. April and October bring consistent Baetis emergences on overcast days, pulling large fish to the surface. PMDs emerge through summer on the quality water stretch. The Pale Evening Dun hatch in June offers some of the most exciting surface fishing of the year, with large fish feeding aggressively in the flats.
Texas Hole, Baetis Bend, and Cable Hole are the most popular access points. Upper sections near the dam see slightly less pressure than the lower pools. The river gets significant weekend traffic year-round. Weekdays in fall and winter offer the most solitude on this storied fishery.
See the full New Mexico Fly Hatch Chart for hatch timing across all of New Mexico's top trout streams.
Check Conditions Near San Juan RiverWhat to Fish
Chironomidae
Midges are the foundation of San Juan River fishing. Year-round emergences keep trout keyed on small flies even when nothing visible is happening on the surface. Peak activity is in winter and early spring, when dense hatches bring fish to the film in the flat sections. Gray, olive, and black are the most common colors. Light fluorocarbon tippet in 6X or 7X and a drag-free drift are non-negotiable.
Recommended: Zebra Midge, RS2, Griffith's Gnat #22-26
Ephemerella infrequens
PMDs emerge on the quality water section from late May through August, with June and July being the most consistent months. Morning and early afternoon emergences draw fish up in the pools and flats. Spinner falls in late afternoon can make fish very selective. Light tippet and a dead-drift presentation are essential. The Chama emerges are not as dense as some tailwaters, but fish respond well on good days.
Recommended: Sparkle Dun, Comparadun #16-18
Baetis sp.
BWOs on the San Juan peak in April and October, typically on overcast or drizzly days. These hatches bring the largest fish in the river to the surface. Even outside hatch windows, a small Baetis nymph under an indicator accounts for fish year-round. Fall BWO fishing in October is some of the best dry fly action of the year, with heavy hatches and less pressure than spring.
Recommended: Sparkle Dun, CDC Dun #18-22
Hydropsyche sp.
Caddis runs from May through September on the San Juan, with peak evening emergences in June. Fish the flats and along the banks during evening flights. An Elk Hair Caddis or X-Caddis in size 14 to 16 is reliable. Soft hackle wet flies swung through the current also account for fish during the caddis window, particularly in the transition from afternoon to evening.
Recommended: Elk Hair Caddis, X-Caddis #14-16
Common Questions
The quality water section runs approximately three and a half miles from Navajo Dam downstream to the Texas Hole public access area. Within this stretch the river is catch-and-release only with artificial lures and flies. Below Texas Hole downstream to Blanco follows standard New Mexico regulations. Most visiting anglers target the quality water section.
Yes, especially on weekends. Texas Hole and Cable Hole see the most pressure. Weekdays, early mornings, and winter months are significantly quieter. Upper sections near the dam tend to receive less fishing pressure than the lower pools. Fall and winter offer the best combination of fish activity and reduced crowds.
Midges dominate most of the year. RS2s, Zebra Midges, and Baetis nymphs in sizes 22 to 26 account for most fish. During hatches, Sparkle Duns and Comparaduns in PMD and BWO patterns cover surface feeding. WD-40s and Sangre de Cristo Midges are locally effective patterns. Light fluorocarbon tippet in 6X or 7X is standard.
Fall and winter are often the least crowded and most productive seasons on the San Juan. October BWO hatches can be excellent, and dense winter midge hatches provide consistent action when most other rivers in the region are blown out. Spring brings more hatch diversity across the quality water section. Summer fishing is good but comes with more pressure and warmer air temps.
Live readings from USGS gages on the river.
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