Colorado ·
New Mexico ·
Rio Grande Fly Fishing Report - September 20, 2026
RIO GRANDE
ReportSEP 20 — 27, 2026
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Flow
36CFS
RIO GRANDE NEAR CERRO, NM
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Water Temp
—
Updated 2026-09-19
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Weather
36–76°F
Mostly Clear
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Clarity
Clear
Check post-storm
The Rio Grande near Cerro is running at a very low 36 CFS with a gauge height of 1.07 ft — expect gin-clear water, spooky fish, and technical presentations. Sunny skies and a high of 76°F make morning the prime window before midday heat slows surface activity.
What's Working — Hot Flies
Juju Baetis Tungsten #22
22
Parachute - Blue Wing Olive #22
22
Olsen's Peacock Blowtorch Barbless #22 - 24
22
Black Zebra Midge(TBH) #20
20
Olsen's Quilldigon - Olive - Barbless #22 - 24
22
Top Secret Baetis #16
16
Egan's Silver Bullet - Baetis #14
14
Bionic Ant 2.0 - Black #16
16
Roza's World Spain Perdigon Barbless #18 - 32
18
Egan's CDC Rainbow Warrior #22
22
Corn-fed Caddis (CDC) Olive #20
20
Olsen's Hare's Ear Blowtorch Barbless #20 - 28
20
Hatch Chart
| Insect | Size | Activity | Prime Time |
|---|---|---|---|
| Trico | 22-24 | Moderate | 7 AM - 10 AM |
| Blue-Winged Olive (Baetis) | 20-22 | Moderate | 9 AM - 12 PM |
| Midge | 20-24 | Heavy | 7 AM - 11 AM |
| Caddis | 16-18 | Light | 5 PM - 7 PM |
| Terrestrial (Ant) | 16 | Light | 11 AM - 3 PM |
Best Time Window
- 6:30 AM - 9:30 AM: Midge and Trico hatch window — fish the flats and tailouts with small dries and emergers before the sun hits the water.
- 9:30 AM - 12:00 PM: BWO activity peaks in shaded canyon sections — nymph the deeper slots and watch for opportunistic risers in slower water.
- 5:00 PM - 7:00 PM: Evening caddis activity along rocky banks — work the riffle tails with a CDC caddis as temperatures drop and fish move shallow.
Guide's Tip
From the benchAt 36 CFS the Rio is running very low and clear — stealth is everything. Downsize to 6X fluorocarbon tippet, stay low, and wade slowly to avoid sending pressure waves upstream. Focus your nymphing in the 12-18 inch depth range in the heads of pools and along current seams where fish are stacked and feeding. If you see risers during the BWO or Trico window, switch to a dry and approach from directly downstream with a reach cast to get a drag-free drift of at least 4-5 feet.
Main Species
Brown Trout
Rainbow Trout
Rio Grande Cutthroat Trout
