The Colorado Winter Fly Box: 10 Patterns You Actually Need

Winter in Colorado doesn’t care about your streamer box or that crate of summer dries.
Once the water dips below 45°, the fish get lazy, the bugs get tiny, and every fly in your box has to earn its place.

So clean house, sharpen your hooks, and build the only winter box that matters.

1. Black Beauty (#22–24)

The MVP of winter. Works in every tailwater in the state.
Dead drift it behind an attractor or drop it solo in glassy runs.

• Best For: Dream Stream, Cheesman, Blue River
• Pro Tip: Add a tiny tungsten bead if the drift feels too fast.

Learn how it fishes on the Dream Stream →

2. Mercury Midge (#22)

The sparkle that seals the deal. That tiny bead head catches light even in low sun.

• Best For: Blue River, Yampa River
• Pro Tip: Fish it as a top fly above a smaller midge; keep it subtle.

See it in action on the Blue River →

3. Juju Baetis (#20)

When trout ignore midges, this BWO crossover closes the deal.

• Best For: Deckers, Yampa River
• Pro Tip: Fish it mid-column — not on the bottom.

Check this week’s Deckers Report →

4. Top Secret Midge (#24)

For when Cheesman Canyon decides to humble you.

• Best For: Cheesman, Dream Stream
• Pro Tip: 7X tippet, no indicator, and a prayer.

Cheesman Canyon details →

5. RS2 (#20–22, Gray or Olive)

Old-school emerger that still fools fish when nothing else will.

• Best For:  Deckers, Dream Stream
• Pro Tip: Trail it behind a Baetis or WD-40.

Learn how to rig it in Midge Madness →

6. WD-40 (#22)

The fly every winter angler swears they invented. Simple, perfect, and deadly.

• Best For: Dream Stream, Deckers
• Pro Tip: A single split shot 12" above makes this drift just right.

7. Zebra Midge (#22–24)

The workhorse pattern when visibility is low or fish are sluggish.

• Best For: Yampa, Bear Creek
• Pro Tip: Use red on cloudy days, black on bright ones.

Yampa River Report →

8. Mini Leech (#12–14, Black or Olive)

The cold-water streamer that earns its keep.

• Best For: Blue, Cheesman, Arkansas
• Pro Tip: Slow strips, long pauses. Fish it like it owes you money.

See it swing in Tailwater Therapy →

9. Egg Pattern (#14–16, Peach or Pink)

Still relevant post-spawn when fish key in behind redds.

• Best For: Dream Stream, Deckers
• Pro Tip: Pair with a trailing midge for a “clean-up crew” rig.

10. Griffith’s Gnat (#22–24)

Because even in winter, some trout will rise.

• Best For: Calm afternoons on the Platte
• Pro Tip: Grease it lightly; let it sit and shimmer.

Bonus Gear Picks

• Tippet: 6X–7X Fluorocarbon
• Leader: 10–12 ft
• Indicator: Small yarn or pinch-on foam
• Rod: 3- or 4-weight with soft tip
• Hands: Thin gloves + hand warmer = sanity

Why This Box Works

You don’t need 200 patterns — just 10 you trust.
Every fly here covers one of three food groups: midges, baetis, or eggs.
The rest? Leave them at home and thank yourself later.