Free Resource · Updated 2026
The complete fly hatch chart for Colorado's premier tailwaters, freestone rivers, and high-altitude fisheries. From the legendary Frying Pan and South Platte to the Colorado River, Roaring Fork, Arkansas, Blue River, Cache la Poudre, Taylor, and Gunnison — select your river below for peak hatch timing, fly pattern recommendations, and current month highlights for 2026.
Colorado Hatch Calendar — Quick Reference
Colorado Rivers
Frying Pan · Blue River · Taylor River · South Platte
Colorado's dam-regulated tailwaters are among the most productive trout fisheries in North America year-round. Cold, consistent releases keep temperatures stable, making midges active through winter and BWOs reliable from early spring through late fall. The Frying Pan below Ruedi Reservoir and the South Platte through Cheesman Canyon are world-famous technical fisheries demanding light tippets and precise presentations to large, selective trout.
Cache la Poudre · Colorado River (Pumphouse) · Roaring Fork
Colorado's freestone rivers track snowmelt and air temperatures, with hatches arriving after runoff subsides — typically mid-June for most streams. These are high-gradient rivers that reward anglers who time their visits after peak flows. Caddis, Golden Stones, and hoppers dominate summer. The Roaring Fork is one of Colorado's best Green Drake rivers in July, and the Colorado River near Pumphouse offers fantastic hopper fishing through August.
Gunnison River · Arkansas River
Colorado's high-elevation rivers offer a compressed but intense hatch season. The Gunnison Black Canyon is legendary for its Salmonfly and Golden Stone hatches in May–June. The Arkansas near Salida and Cañon City produces excellent Golden Stone and Caddis fishing. Higher elevation means a shorter season — hatches run later and finish sooner — but the wild, powerful fish and stunning scenery make these rivers worth the planning.
The Why Behind the Chart
Baetis sp.
Colorado's most consistent hatch and the bread-and-butter of tailwater fishing from late winter through late fall. BWOs thrive on overcast, drizzly days when barometric pressure drops — exactly the days that seem least promising. On the Frying Pan and South Platte, BWOs can hatch as early as February during warm spells and continue through November. Fish the emerger in the film rather than the adult on the surface for the best success with Colorado's selective tailwater trout.
Recommended: #18–22 Sparkle Dun, RS2 Emerger, CDC Dun
Ephemerella inermis
Colorado's signature summer mayfly, hatching on virtually every river in the state from June through August. PMDs emerge in the morning on tailwaters and through midday on freestone streams when the hatch fires consistently. The South Platte through Cheesman Canyon, the Frying Pan, and the Roaring Fork all produce excellent PMD hatches. Match the dun in the morning; switch to the spinner fall in the afternoon as fish sip spent wings in the film.
Recommended: #16–18 PMD Comparadun, Sparkle Dun, Cripple
Drunella grandis
Colorado's most legendary hatch and the event that draws anglers from across the country each summer. Green Drakes emerge in July on the Frying Pan, Colorado River, and Roaring Fork — large, olive-bodied mayflies that trigger some of the most aggressive surface feeding of the season from even the most selective trout. The hatch fires in the afternoon and can continue into evening. The Roaring Fork near Basalt is particularly renowned for this hatch.
Recommended: #10–12 Green Drake Paradrake, Comparadun, Lawson's
Hydropsyche sp.
Caddisflies are the workhorse hatch across Colorado's freestone and tailwater rivers from late May through August. Evening caddis hatches on the Colorado River, Cache la Poudre, and Arkansas produce explosive surface feeding. A soft-hackle or caddis pupa swung through the current at dusk is often more effective than a dry. On tailwaters like the Frying Pan, caddis hatch can be the best surface action of the summer evenings from June through August.
Recommended: #14–16 Elk Hair Caddis, X-Caddis, LaFontaine Sparkle Pupa
Chironomidae
Colorado's tailwaters are midge fisheries at their core. The Frying Pan, Blue River, Taylor, and South Platte all produce year-round midge hatches that are the primary food source for trout through winter. Midges cluster on the surface forming "midge mats" that trout sip from with rhythmic rises. Use small clusters (#18–20 Griffith's Gnat) or individual pupae (#22–28). Winter midge fishing on Colorado tailwaters is a world-class technical challenge.
Recommended: #22–28 Zebra Midge, Mercury Midge, Griffith's Gnat
Melanoplus sp.
Hopper season is one of Colorado's most beloved fishing events, running July through September on freestone rivers across the state. The Colorado River near Pumphouse and Radium, the Gunnison, and the Arkansas near Salida are the top destinations. Fish large, bushy patterns close to grassy banks in the afternoon heat — trout key on the splashdown of hoppers falling from streamside vegetation. Combine a hopper with a dropper nymph for maximum effectiveness.
Recommended: #8–12 Parachute Hopper, Dave's Hopper, Chernobyl Ant
Colorado's tailwaters are among the most productive trout fisheries in North America year-round. Rivers like the Frying Pan and South Platte produce prolific midge hatches throughout winter, and Blue-Winged Olives begin as early as February on warm days — offering some of the most technical dry fly fishing in the West on tiny flies to heavily pressured, selective trout. The Taylor River and Blue River below Green Mountain Reservoir offer similar year-round opportunities.
Spring opens the season on freestone rivers: caddisflies begin hatching in May on most rivers, followed by Pale Morning Duns through summer. The Green Drake hatch in July on the Frying Pan, Roaring Fork, and Colorado River is legendary — large mayflies that trigger some of the most aggressive surface feeding of the season. Golden Stoneflies on the Arkansas and Gunnison provide exciting big-dry-fly action in June, and the Gunnison's Salmonfly hatch is one of Colorado's most spectacular events.
Hopper season runs July through September on the Colorado River, Arkansas, and Gunnison, followed by fall BWOs from September through November. Pair this chart with FlyFishFinder's live gauge data to know when flows and water temperatures are ideal on your target Colorado river.
See Live Colorado River Conditions →Common Questions
Green Drakes typically hatch on the Frying Pan in July, peaking in the middle of the month. The hatch fires in the afternoon when water temps are right and can produce exceptional dry fly action from the large, selective trout in Ruedi Canyon. Fish a #10–12 Paradrake or Green Drake Comparadun. The Colorado River near Pumphouse and the Roaring Fork also produce Green Drake hatches around the same time.
Winter on the Frying Pan, Blue River, South Platte, and Taylor calls for midges above all else. Use #22–28 Zebra Midges, WD-40s, and Mercury Midges in the film. BWOs can fire on warm winter afternoons — keep a #20–22 Sparkle Dun or CDC Dun handy. Nymphs like San Juan Worms and Pheasant Tails work through cold periods. The tailwaters fish year-round, but winter requires patience and a delicate approach.
Hopper season runs July through September on Colorado's freestone rivers. The Colorado River near Pumphouse and Radium, the Gunnison, and the Arkansas River near Salida offer the best hopper action. Fish along grassy banks in the afternoon when hoppers are most active. Combine a hopper dry with a dropper nymph for the most productive setup.
Cheesman Canyon on the South Platte is a world-class tailwater that fishes well year-round. Spring brings BWO hatches in March–May, often on overcast afternoons. Midges remain active throughout. By late May and June, caddis begin hatching in the evening. The fish are notoriously selective and the canyon requires technical presentations with light tippet (5X–7X) and careful wading.
The Roaring Fork is best known for its Green Drake hatch in July near Basalt and Carbondale. PMDs hatch through June–August. Caddis are a staple all summer. Hoppers become effective in August along meadow stretches. The Roaring Fork fishes well from Basalt downstream after runoff clears, typically late June through September.
Colorado's tailwaters fish year-round — the Frying Pan and South Platte are excellent even in January and February for midge specialists. The best overall dry fly season runs June through September. BWOs and midges provide top action in March–May and again September–November. Green Drakes and hoppers peak in July, making it arguably the single best month for Colorado dry fly fishing.
FlyFishFinder combines hatch knowledge with live gauge alerts, Prime condition indicators, and real angler intel — so you show up on the right day, not the wrong one.
Start Your Free TrialFree Trial · Cancel Anytime · $0 Charged Today