What Flies Work Best in October in Colorado?

Fly fishing in Colorado doesn’t stop when summer ends. In fact, October might be one of the most productive and underrated months to fish in the Rockies. With cool temperatures, hungry trout, and fewer crowds, it’s a great time to hit the water.

If you’re wondering what flies work best in October in Colorado, this guide breaks it down by fly type, hatch activity, and water conditions, plus pro tips from the team at Kirks Flyshop, your go-to outfitter in Estes Park for guided fly fishing trips, private water access, Colorado River floats, and fly fishing classes.

Why October is a Great Time to Fly Fish in Colorado

October brings a perfect mix of conditions that set the stage for exceptional fly fishing:

  • Cooler water temperatures = more active fish

  • Trout feeding aggressively to bulk up before winter

  • Brown trout spawn begins, making them more aggressive and territorial

  • Less fishing pressure with fewer tourists on the water

  • Consistent hatches of midges and Blue Winged Olives (BWOs)

Whether you’re exploring high-country streams or booking a float trip on the Colorado River, October fishing in Colorado offers rewarding days and often your best chance at a trophy.

Best Fly Types for October in Colorado

1. Streamers

Streamers are a top pick in October, especially when targeting aggressive pre-spawn brown trout.

Why they work:
Trout are more territorial during spawning season and will chase down larger flies like streamers out of both hunger and aggression.

Top Patterns:

  • Woolly Bugger (black, olive, white)

  • Sparkle Minnow

  • Sculpzilla

  • Peanut Envy or other articulated patterns

When to use:
Low-light hours (early morning, late afternoon) or during overcast days.

2. Nymphs

Nymph rigs remain productive all month long and are perfect when trout are feeding deeper in the water column.

Top Patterns:

  • Pheasant Tail Nymph

  • Prince Nymph

  • Flashback Hare’s Ear

  • Zebra Midge

  • Rainbow Warrior

  • Egg patterns (especially near spawning browns)

How to fish:
Double nymph rig under an indicator, or tight-line nymphing in riffles and seams.

3. Dry Flies

While dry fly action slows compared to summer, warm October afternoons can still bring fish to the surface.

Look for:

  • BWOs (Blue Winged Olive) hatching midday

  • October Caddis (in select rivers)

  • Midges on stillwater or calm stretches

Top Patterns:

  • Parachute BWO

  • CDC Comparadun

  • Griffith’s Gnat

  • October Caddis (size 10–12)

Want help identifying what’s hatching? Join a fly fishing class or take a guided trip to learn real-time tactics from local pros.

Best Places to Fish in October

Looking for the best water to throw your fall flies? Here are top options guided by the team at Kirks:

Big Thompson River (Walk & Wade)

Rocky Mountain National Park

  • Wild, native trout in high alpine streams and lakes

  • Lower elevations fish well through mid to late October

Private Water Access

  • Less pressure, bigger fish, exclusive beats

  • Available on the Big Thompson through Kirks Flyshop

Colorado River Float Trips

October Fly Fishing Tips from Kirks Guides

  • Fish during the warmest part of the day (10 a.m. – 3 p.m.)

  • Use 5X or 6X tippet for small flies like midges or BWOs

  • Pack layers – mornings are cold, afternoons can be sunny

  • Don’t overlook egg patterns – they can be deadly near spawning fish

  • Focus on structure: pools, seams, cutbanks, and deep runs

  • Use polarized sunglasses to spot fish and reduce glare

🎒 Need gear? Rent boots, waders, and rods from Kirks, perfect for travelers.

FAQs: Fly Fishing in Colorado in October

Which hatches should I expect when fly fishing in Colorado in October?

Key fall hatches include:

Blue Wing Olives (BWOs) – Most consistent hatch, active midday to afternoon

  • Midges – Present all day, especially on sunny or calm days

  • October Caddis – Sporadic but effective, especially in freestone rivers

  • Tricos – May linger early in the month, primarily mornings

Do I need a Colorado fishing license in October?

Yes. A valid Colorado fishing license is required year-round for anyone age 16 or older.

Are October guided trips still available at Kirks Flyshop?

Absolutely. We guide walk-and-wade, private water, float, and Lake Estes fishing charters throughout October (weather permitting). Fall is a favorite among our guides.

What time of day is best to fish in October?

Mid-morning through mid-afternoon is typically most productive. Cooler overnight temps mean fish are more active once the sun hits the water.

Do trout still rise for dry flies in October?

Yes, especially on overcast days or warm afternoons. BWOs and midges are your best bet for surface eats.

What flies should I pack for an October trip?

A well-rounded October fly box should include:

  • BWO dries and emergers (sizes 18–22)

  • Zebra midges (sizes 18–20)

  • Pheasant Tails and Hare’s Ears (sizes 14–18)

  • Streamers like Woolly Buggers and Sparkle Minnows

  • Egg patterns for nymph rigs

Is October a good time for beginners?

Yes! With less pressure on the water and hungry trout, October is an ideal time to learn. We recommend booking a fly fishing class or half-day guided trip for hands-on support.

Book Your October Fly Fishing Adventure with Kirks Flyshop

October is one of Colorado’s hidden gems for fly fishing, cool temps, vibrant foliage, and actively feeding trout await.

🎣 Whether you’re looking to float the Colorado River, walk-and-wade in Rocky Mountain National Park, or explore private access on the Big Thompson, Kirks Flyshop has you covered.

✅  All gear provided
✅  All skill levels welcome
✅  Expert local guides
✅  Trips available daily in October

👉 Check trip availability and book online now or contact us for help planning your October fishing experience.