Trico season arrives on Colorado's South Platte as tailwaters run low and clear

What's biting

What's next

The next several days on both tailwaters will reflect the same low, clear character that has defined this season. Flows on the South Platte and Arkansas remain stable, as dam-regulated tailwaters are insulated from the dramatic swings that affect freestone streams, but expect them to run below historical averages given the low-snowpack conditions Cutthroat Anglers described as "the topic of discussion everywhere we go."

Along the South Platte and Dream Stream corridor, the morning window is the one to target. Trico spinner falls build through late June and typically peak through July, cresting between roughly 8 and 10 a.m. on calm, clear days. Under current low, clear conditions, fish will be sipping spinners with selectivity: size 22 to 26 Trico patterns, spent-wing or CDC film styles, on 6X or 7X fluorocarbon. Gink and Gasoline documented how overwhelming these South Platte spinner falls become, with trout keyed so tightly to the surface film that sub-surface offerings go unnoticed. Arrive early, move deliberately, and let the fly do the work.

AvidMax Blog's current tying rotation, including Titan Tube Midges, Chocolate Foam Back emergers, and the Jigged CDC PT Tungsten, maps directly onto what tailwater trout want in these conditions. The Chocolate Foam Back, designed to ride just below the surface film, is a strong choice between trico windows or when fish are feeding on midge emergers rather than spinners.

On the Arkansas tailwater, expect mid-morning PMD hatches and afternoon caddis as the dominant dry-fly events by late June. Low water makes tippet choice critical: 6X fluorocarbon is a better default than 5X. Cutthroat Anglers advises casting lighter across the board, and the pressured fish in clear, shallow flows will confirm that advice quickly. Evening sessions from 6 to 8 p.m. often produce caddis dry-fly action even when midday fishing slows in summer heat.

The waxing gibbous moon heading toward full may boost low-light feeding activity at dawn and dusk on both rivers. Watch for afternoon thunderstorms, a late-June Colorado fixture, which can trigger aggressive feeding in the hour before they arrive as barometric pressure drops. After any storm, check conditions on the Arkansas before returning, as runoff from tributaries can temporarily cloud the river. South Platte tailwaters, regulated by reservoir releases, are more insulated from that impact.

Context

For the South Platte and Arkansas tailwaters, late June is traditionally among the most productive technical fly-fishing windows of the year in Colorado. Runoff on the state's freestone streams typically peaks in late May through mid-June; by the final week of June, regulated tailwaters are often the clearest and most fishable option while other rivers remain off-color. This year, that transition arrived ahead of schedule. Cutthroat Anglers called this winter "historic for all the wrong reasons" in terms of snowpack, describing it as the topic of discussion throughout the guiding community. A leaner runoff cycle pushed South Platte and Arkansas flows into low-clear territory earlier than most seasons, compressing what is normally a gradual summer transition.

The Dream Stream section, running between two reservoirs and widely regarded as one of Colorado's premier trophy tailwater stretches, typically sees its most celebrated fishing during spring and fall as large browns and rainbows push out of the reservoirs. Colorado Trout Hunters noted this past spring's run as one of the best in recent memory. By late June, most of those migratory fish have returned to deeper reservoir water, and the fishery shifts toward resident trout in technical, sight-fishing mode.

The South Platte's trico hatch is a regional institution. Gink and Gasoline, writing about an early trico experience on the river, described the spinner density as something that "put me in a frozen trance," holding dozens of insects from a single scoop across the surface film. Late June through August is the core window for that event, meaning the timing of this report coincides with the opening act of one of the river's most anticipated annual hatches.

Finally, MidCurrent reported in 2026 on the Tolland Ranch conservation acquisition, which expands public fly-fishing access to previously private South Platte headwaters water. That deal does not change current fish behavior, but it does add fishable mileage to this corridor and represents the kind of long-term access investment that keeps Colorado's tailwaters among the most productive in the West.