Cache la Poudre River Report – Low Flows, Tight Lines & Mayfly Action (Sept 15, 2025)

Flowing through Colorado’s stunning Front Range, the Cache la Poudre River is a rugged, scenic waterway known as Colorado’s only Wild and Scenic River.

The river is flowing pretty skinny—24 cfs at the canyon mouth, 14 cfs in Fort Collins, and lower still below Seaman Reservoir. Water is crystal clear, so anything flashy or bulky spooks fish; small, precise offerings are working best. Mornings still bring mayfly activity, BWOs and PMDs, with dry-dropper rigs and emergers doing heavy lifting. Terrestrials are slowly creeping in for afternoon interest. Pressure is moderate through the canyon, increasing near popular access points.

At-a-Glance Conditions

Rating: ⭐⭐☆ — great potential but tight conditions demand finesse
Flow (CFS): 24 (canyon mouth) | 14 (Fort Collins) | ~2 (North Fork below Seaman) St. Peter's Fly Shop
Water Temp: ~62°F at many Fort Collins pull-offs (daytime) Rocky Mountain Anglers
Air Temp: Mid-70s°F to low-80s°F in daytime, cooler in early/late day risebeyondflyfishing.com+1
Clarity: Clear St. Peter's Fly Shop+1
Best Times: 6:30–10 AM (mayflies, PMDs) | Evening (terrestrials, emergers)
Fishing Pressure: Moderate — more along lower canyon and Fort Collins bank; quieter upstream & canyon sections
Top Flies: RS2 #20 | Bead-Head Prince #16 | Flashback Hare’s Ear #18

🎧 Listen to the Podcast

Cracking the Cache - Fall Poudre Edition – Skinnies, Emergers & Mayfly Windows
Flows are low, visibility is high, and trout are watching everything. We talk exactly which bugs are fooling fish now, what rigs are working, and where to sneak in for less pressure.

Weather Snapshot

(Embed local NOAA / OpenWeather for Fort Collins / Canyon) 

Poudre River Hatch Chart 

Flies for the Poudre River

• Dry Fly Setup: Bead-Head Prince #16 or E.C. Caddis #14–16; long leader (12-14 ft), 6X tippet.
• Nymph Setup: Flashback Hare’s Ear #18-20 or Tunghead Pheasant Tail #16-18; use dry-dropper or two nymphs; tiny emerger add-on works well.
• Streamer Setup: Slumpbuster #8, Mini Gonga #6-8; swing shady banks or deep structure near slower flows.
• Pro Rig (Guide’s Pick): A flashback double nymph: Prince #16 + Hare’s Ear #18 with a small dropper or bead to get down where fish are holding.

Access Points

Extended FAQ – Cache la Poudre

Q: What’s the best time to fish the Poudre in mid-September?
A: Morning hatch windows (6:30-10 AM) for Tricos / mayflies / PMDs; evenings for terrestrials if temperatures dip.

Q: Which flies are working best right now?
A: RS2s, Bead-Head Prince, Flashback Hare’s Ear, E.C. Caddis, and small emergers and PMDs #18-20.

Q: How important is tippet & leader right now?
A: Very. 5X-6X fluoro or fine monofilament, long leaders (12-14 ft) help with drag and presentation in super clear water.

Q: Are there sections worth avoiding?
A: Lower Fort Collins sections have more traffic and occasional fine particulate / graze from irrigation; better to fish upstream in canyon when possible.

Q: Any regs I should know?
A: Standard fly/lure only in many stretches; be aware of special regs near the Hatchery Section & North Fork below Seaman; always check CPW before heading out.

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