Trout eat what the river serves them, and your job as an angler is to match that menu. Getting the hatch right is often the difference between a slow day and a memorable one on the Gunnison and Taylor. This GunnisTrout eat what the river serves them, and your job as an angler is to match that menu. Getting the hatch right is often the difference between a slow day and a memorable one on the Gunnison and Taylor. This Gunnison River hatch chart gives you a practical, season-by-season roadmap for what flies to use throughout the year.
Think of it as a starting point, not the final word. Hatches shift with weather, flows, and water temperature, so this Colorado fly fishing hatch chart works best paired with real-time local knowledge. When you know the general timing and let a guide fine-tune the details, you show up ready to fish smart.
Winter (Dec–Feb): Midge Season
Cold water slows everything down, and midges become the dominant food source. Fish small Zebra Midges, RS2s, and Griffith’s Gnats in sizes 20 to 26. Focus on deep, slow runs and the warmest part of the day, usually late morning through early afternoon.
Early Spring (Mar–Apr): BWOs Arrive
As days lengthen, Blue Winged Olives join the midges. Cloudy, overcast afternoons trigger the best mayfly activity. Carry small BWO emergers and dries alongside your midge patterns, and watch for subtle rises in soft seams.
Runoff (May–early Jun): Nymphing Focus
Snowmelt pushes the river high and off-color, so dry fly action is limited. This is prime nymphing time. Tie on bigger, visible patterns like stonefly nymphs, San Juan Worms, and beadhead attractors to reach fish holding along softer edges.
Early Summer (Jun–Jul): The Big Bug Window
Once flows drop and clear, the river comes alive. Caddis, Pale Morning Duns, and golden stoneflies all show up. This is one of the best stretches of the year for dry fly fishing, especially during evening caddis activity.
Mid-Summer (Jul–Aug): Terrestrials and Attractors
Warm afternoons bring hoppers, ants, and beetles tumbling into the water. Fish terrestrials tight to grassy banks, and mix in attractor dries like a Parachute Adams or a Royal Wulff. A hopper-dropper rig covers two food sources at once.
Fall (Sep–Oct): Streamers and Late BWOs
Cooling water turns brown trout aggressive as they prepare to spawn. Strip streamers near banks and structures for the biggest fish of the season. On cloudy days, late Blue Winged Olives offer excellent dry fly action.
Quick-Reference Guide
Use this at-a-glance summary when you pack your box:
- Winter: Midges (Zebra Midge, RS2), size 20–26, midday
- Early Spring: BWOs and midges, size 18–22, overcast afternoons
- Runoff: Stonefly nymphs, worms, size 8–14, all day
- Early Summer: Caddis, PMDs, golden stones, size 12–16, evenings
- Mid-Summer: Hoppers, ants, beetles, size 10–16, warm afternoons
- Fall: Streamers and late BWOs, size 6–20, midday to dusk
Building a Starter Fly Box
You do not need hundreds of patterns to fish well here. Start with a solid core: a few Zebra Midges, RS2s, and Pheasant Tails for nymphing, plus Elk Hair Caddis and Parachute Adams for dries. Add a couple of stonefly nymphs, a hopper or two, and a Woolly Bugger, and you can cover most conditions the valley throws at you.
Round out your selection in the colors and sizes noted above, and you will be prepared across all four seasons. From there, you can build depth in whichever hatches you enjoy fishing most.
Not sure what’s hatching right now? Book a guided trip and let us do the matching for you.