October 2025 San Juan River Update

Flow: 350 CFS
Conditions: Excellent

As of October 8th, the San Juan River is running at 350 cubic feet per second, setting up some of the most ideal fly fishing conditions of the entire year. With consistent flows, clear water, and comfortable autumn weather, anglers are enjoying a stretch of exceptionally productive fishing across all sections of the river.

What’s Hatching & What to Throw

The San Juan’s trout are feeding actively throughout the day, and this week’s bug activity has been impressive:

• Morning Midges: Early hours are dominated by midge pupa and larva. Stomach samples confirm that midges remain the most reliable food source right now. Carry plenty of small patterns in sizes 22–26, especially cream, black, and gray variations. Your favorite red larva pattern in a 16 or 18 is also an excellent choice before 10am.
  
• Afternoon Mayflies: As the day warms and light levels shift, strong Baetis and mayfly hatches have been coming off, particularly on cloudy afternoons. A well-presented dry fly will fool some of the rivers most technical trout — look risers along the seams and soft edges. A last chance cripple in 18 has been our most productive dry fly as of late.
  
• Streamer Success: For anglers who like to throw meat, the streamer bite has been very consistent. Early morning and late evening are the sweet spots. White, black, and olive streamers have all been producing — and a subtle twitch or slow swing often seals the deal.
  
• Dry Fly Action: Don’t overlook dry flies altogether. Larger patterns like Chubby Chernobyls and high-vis parachutes are pulling fish from the surface, especially in faster water or riffle transitions.
  
• Scuds & Seasonal Transition: As fall progresses and aquatic vegetation begins to die, scuds become a more prominent part of the trout diet. Keep some gray scud patterns in size 18 and 20 on hand during the next few months.
  
• Upcoming Baetis Hatch: Expect the Baetis activity to continue through mid-December, keeping dry fly enthusiasts happy until about the middle of December.

(This brown trout ate a swung streamer early morning in the quality water)

Tips from the About Trout Crew

• Start your morning with small midge rigs in the upper sections.
  
• Switch to mayfly emergers and dries as the day warms.
  
• Don’t hesitate to throw streamers in low light — big fish are on the move.
  
• Keep an eye on flows, but 350 CFS is about as good as it gets for wade anglers.

October on the San Juan River offers everything an angler could want — active fish, technical dry fly opportunities, and stunning fall scenery. Whether you’re hunting for dry fly eaters or just soaking in the colors of the canyon, this is a month that reminds us why we love this river so much.

If you’re ready to experience it for yourself, our About Trout guides are on the water daily and would love to share the season with you.