Colorado Fall Fly Fishing: Key Hatches and Tips for Success

Colorado Fall Hatch Chart & Guide

Fall in Colorado is not the “death” of hatches — it’s a narrowing of the field. Big bugs fade, but a few key hatches carry through, especially BWOs, midges, October caddis, and the occasional PMD or Trico remnant. If you match them and fish clean, dry-fly days are still in play.

 

• Start subtle. In fall, trout are cautious. Begin with midges or BWO emergers before jumping to dries or streamers.
• Watch the clouds. BWOs often pop under overcast skies.
• Match size downward. Fall variants tend toward smaller individuals.
• Edge water & slack seams. Many hatches (especially October caddis) start near banks, sloping seams, slower edges.
• Switch mid-day if needed. If dries wane, drop into emergers or nymphs in exact hatch profiles.
• Evening blitzes matter. October caddis and midges often push big trout at last light.
• Don’t ignore midges. They feed fish when bigger hatches shut off.
• Terrestrials fade. Ants, beetles decline; rely less on them as October deepens.

• Tailwaters (Blue, Frying Pan, South Platte lower) — stable flow favors BWO and midge activity, especially in mid-day.
• Freestones / Mid-Elevation Rivers — October caddis tend to appear in calmer water, braided edges, and near banks.
• High Elevation Streams — midge dominance persists; bug size shrinks. Dry-fly windows narrow.
• Urban / pressured rivers (Clear Creek, Boulder) — more selective; micro patterns and stealthy drifts win.

• You’re not “too late.” Fall may be leaner, but it’s often the clearest one.
• Fall is about timing, not quantity. One good dry drift is better than 200 off-target casts.
• Dress double. Early cold, midday sun, evening chill—layer.
• Night fishing? Sometimes works for caddis remnants; flashlight drifts can spark takes.
• Walk smart. Fish see shadows—don’t spook them by stepping into their lanes.

Listen to the Podcast! Colorado Fall Hatch Chart (Type | Size | Color(s) | When to Fish / Conditions | Tactical Notes)Hatch / InsectTypical Size(s)Color(s) / ToneBest Window (Time & Conditions)How to Fish It / NotesMidges / Midges#20 – #24Black, Olive, Gray, PearlAll day, especially when nothing else is activeGo light—single or dropper. Try emergers or beadhead versions. Keep them subtle.Blue Winged Olives (BWO / Baetis)#18 – #22Olive / gray / greenish oliveOvercast or light rain, late morning to early afternoonParachute, comparadun, emerger rigs. Strong “backup” hatch in fall.October Caddis / Late Caddis#12 – #16Tan, Light Olive, BrownDusk to evening; often in slower seams or near banksSkate dries, twitching emerger droppers. Watch edge water.Tricos (linger)#22 – #24Black / white wingEarly morning in protected water (very localized)Use tiny spinners or CDC versions; subtle presentation.PMD (remnants, small)#18 – #20Pale Tan / Light OrangeCloudy afternoons, mild daysEmerger / cripple styles behind dries. Use light hook and delicate drift.Caddis Larvae / Pupae#14 – #18Olive, Tan, BrownBeneath surface, especially near rifflesDropper rigs under dries; add weight to reach depth.Streamers / Baitfish imitations#8 – #12Olive, Brown, BlackLate evening / low light or when fish get lazyShort strips, swing through deep edges, pauses. Good for bonus fish. Tips for Using This Hatch Chart Well
 Fall Hatch Highlights by Region / River Type
 Example Fly Box & Starter Patterns (Fall Core Box)RolePattern SuggestionSize / ColorNotesMidge / Kit FlyZebra Midge, Black Beauty#22–24, black/silverAffordable, productive fallbackBWO / EmergerBarr’s BWO Emerger, Sparkle Wing RS2#18–22Cover BWO windowsDry / CaddisOctober Caddis Adult, Parachute Adams#14–16 (caddis), #18–20 (BWO)Skaters & soft profilesNymph / DropperFlashback Pheasant Tail, Two-Bit Hooker#16–18Anchors or trailersStreamerMini Leech, Slumpbuster#10–12Evening / bonus fish Real Advice