In this report
Flow at 276 CFS: Upper End of Prime, But Watch Water Temp This Week
The gauge is reading 276 CFS—squarely in the upper half of the sweet zone for Cheesman Canyon, where fish are spread across their summer lies and wading remains manageable across most pocket water. This is where the canyon fishes its cleanest: good current separation without the shoulder-high push of higher water, and enough volume that you’re not crowding into a handful of micro-slots where every trout has memorized every angler’s cast.
That said, early June water temperatures on a tailwater below Cheesman Dam run cool—typically in the low to mid-50s—but they’re climbing. If we get a stretch of warm, high-altitude sun and stable weather, the shallow seams and exposed rock will warm faster than the deeper slots. This is not yet a crisis week, but it’s the week to start paying attention. Fish the deeper granite pockets in the afternoon if the sun is strong. The morning window is genuinely valuable right now; don’t waste it on marginal water. If you’re heading in mid-day, focus on the shaded side of boulders and the faster chutes where temperature stratification gives you a cooler lane.
PMD Emergence: Late Morning into Early Afternoon, Small and Selective
Pale Morning Duns are the marquee hatch right now—#16 and #18, mostly emergers and duns. On Cheesman, this is not a blizzard emergence; it’s a precision event. The canyon’s heavy education level means the trout have sorted through thousands of phony PMD presentations. They will refuse a #16 that’s tied heavy, overdressed, or riding too high.
Expect the emergence window to open around 10 a.m. and peak between 11 a.m. and 1 p.m., depending on cloud cover and air temperature. The emergers will be the first wave—cripples and stillborn duns struggling in the surface film. Fish a #18 PMD emerger (soft-hackle or CDC, thinly dubbed body) in the slick seams and bubble lines formed where fast water meets slower holds. At 276 CFS, these seams are well-defined and stable; you’ll see them clearly among the boulders. Cast upstream and slightly to the side; let the fly ride the current line with minimal drag. If you see a rise or a nose, you’re in business. If nothing happens in three good drifts, move.
The true adult dun hatch follows the emerger phase by 20–30 minutes. Switch to a #16 or #18 PMD dry—sparse tie, CDC wing if you can keep it dry—and work the softer edges of pocket water where the current has slowed slightly. This is not a dry-fly bonanza; expect 30–40% of rises to be refusals. The trout are eating, but they’re eating selectively. Match the hatch tightly and accept that some fish will reject you anyway.
The Nymph Game: Small, Weighted Anchor with Emerger Dropper
Nymphing remains the foundation of Cheesh fishing, especially early in the day before the PMD emergence and during the afternoon lull. This is where light tippet and small flies define success.
Rig a two-fly setup: a heavier #18–20 Barr’s Emerger or Pheasant Tail as your anchor point, weighted with 1–2 wraps of .015 lead wire on the shank (or none if you’re comfortable with split shot), and a #20 or #22 PMD emerger or midge as your dropper, tied 18–24 inches above on 4X fluorocarbon tippet. The anchor fly does the work; the dropper accounts for fish intercepting in the film on the way down.
Depth is the puzzle at 276 CFS. In the deep granite slots—the runs where the boulder-formed pocket is clearly 4+ feet deep—add a single split shot 12 inches above the anchor fly. Fish tight-line: no indicator, mend aggressively, and feel for the tick. Cheesman trout will take emergers and nymphs on a dead-drift swing into shallow holding water, but they will reject anything that looks weighted too much for the current. If you’re hanging bottom every other cast, you’re weighted wrong for that run. Move and adjust.
In the shallower, faster seams (2–3 feet, visible bottom), drop the split shot or fish weightless. Use an indicator here if you want; this water forgives it because the current is visible and the trout’s window is narrow. Most guides and locals on this water fish tight-line for better feel, but if you need the visual reference, a small yarn indicator or pinch of foam is legitimate.
Tippet size matters more here than elsewhere. 5X (.0070”) is the minimum; 6X (.0059”) is standard for the true small-fly work in low-light and slow slots. Don’t cheap out. You’re fishing light because the trout demand it, and a spool of good fluorocarbon will last you ten trips.
Caddis and Midge Fill the Gaps—Evening and All Day
Caddis (#14–16) will start emerging in the evening, probably 6–8 p.m., depending on warmth. This is not a hatch to arrive for; it’s a bonus if you’re already in the canyon. Fish tan or olive caddis dries (elk hair, stimulator style) in the faster, more broken water. Caddis trout on this water are more aggressive than PMD trout; they will chase a fly slightly if it looks real.
Midges run all day. #20–24 black or olive emergers, both nymphed and fished in the surface film, will produce throughout the week whenever you’re between hatches. The RS2 emerger in black is a Cheesh classic and a confidence fly; tie one on whenever you’re not working a specific mayfly emergence. Midge dries (#24, simple tie, dark) will take fish in the slower, clearer slots during low-light or when surface activity is visible.
Access and Stewardship: Respect the Hike, Respect the Fish
The Gill Trail is steep and technical in sections; it’s six miles round trip, and the hike out is harder than the hike in. Bring water, bring a headlamp if you’re staying into the evening for caddis, and bring a solid pack. This is not a walk; it’s a commitment. Start early enough that you’re comfortable returning before dark.
Water temperature is climbing into the welfare zone. Fish the early morning hard. If you’re handling fish extensively, wet your hands before each touch, keep your air-time to under 30 seconds, and consider leaving a fish alone if it’s gulping air near the surface. Catch-and-release only, and this water was pioneering in that ethic—honor it.