Free Resource · Updated 2026

Colorado River Fly Hatch Chart

The Colorado River above Kremmling is a wild, less-pressured stretch with consistent hatches and strong trout. The Pumphouse and Radium sections offer long floats through remote canyon water. This is a river worth the drive for anglers looking for solitude during hatches.

Brown Trout, Rainbow Trout Freestone Pumphouse, Radium Current Month Highlighted

Colorado River Hatch Calendar — Quick Reference

About Colorado River

The Colorado River in this stretch runs through high desert canyon country with steep walls and sage-covered banks. It fishes best as a float trip out of Pumphouse or State Bridge. Bank access is limited but the river rewards those who get in a raft or drift boat.

Caddis are the dominant summer hatch and the evening rises can be impressive. The river also sees a Stonefly hatch in late spring that brings up some of the larger trout. Golden Stoneflies are more common here than the big Salmonflies that get all the press.

Fall is a great time to wade the accessible sections near Pumphouse. BWO hatches happen through October and the brown trout are active. Water temperatures stay favorable longer here than on higher-elevation rivers.

See the full Colorado Fly Hatch Chart for hatch timing across all of Colorado's top trout streams.

Check Conditions Near Colorado River

What to Fish

Colorado River Key Hatches

Golden Stonefly

May to June

Golden Stoneflies are the first big hatch of the season on the Colorado River. They are more common here than Salmonflies and the hatch lasts longer. Fish big attractor patterns near the banks in the morning when adults are ovipositing.

Recommended: Golden Stone, Stimulator #6-10

Caddis

May to September, peak June to August

Summer Caddis hatches are the defining event on the Colorado River near Pumphouse. Evening hatches bring fish up along the entire canyon stretch. Float trips during Caddis season give you access to miles of rising trout. Bring plenty of Elk Hair in multiple sizes.

Recommended: Elk Hair Caddis #14-18

Yellow Sally

June to August

Yellow Sallies show up mid-summer and are often overlooked. When they hatch, trout key on them selectively. A size 14 or 16 Yellow Sally fished through choppy runs mid-day can take fish when nothing else is working.

Recommended: Yellow Sally #14-16

Blue-Winged Olive

March to May, September to November

Fall BWO hatches on the Colorado River are underutilized. The crowds that hit the South Platte during fall BWOs rarely make it out to this stretch. October days with overcast skies can produce excellent dry fly fishing with virtually no other anglers.

Recommended: Parachute Adams, RS2 #18-22

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