June Hatch Guide: A Complete Guide to Colorado's Hatches in June

June is one of the most exciting months of the year for Colorado fly anglers. Rivers are transitioning from spring into summer, runoff conditions vary from watershed to watershed, and trout have a diverse menu of aquatic insects available throughout the day.

Whether you're fishing the Eagle River, Colorado River, Roaring Fork River, or your local tailwater, understanding what insects are active and how trout feed on them can dramatically increase your success on the water.

In this guide, we'll break down the most important June hatches in Colorado, including their life cycles, appearance, timing, and how to imitate them effectively.

Midges

Overview

While many anglers associate midges with winter fishing, they remain an important food source throughout June. Midges hatch every month of the year and continue to provide consistent opportunities for trout, especially during slower periods between larger hatches.

Because midges are abundant and available year-round, trout rarely ignore them.

Hilbert’s “Day Saver Midge” is an excellent imitation when trout are keyed in midge pupa.

Life Cycle

Midges undergo a four-stage life cycle:

1. Egg

2. Larva

3. Pupa

4. Adult

The larval stage lives in the river bottom where trout feed on them constantly. As they mature, they rise through the water column as pupae before emerging into adults on the surface.

Most trout feed heavily on the pupal stage because the insects become vulnerable while ascending to the surface.

Midge larvae range in a variety of colors. Be sure to have several colors in your box to match what you find on the river!

What They Look Like

Midge larvae are small, worm-like insects typically ranging in color from:

• Red

• Olive

• Brown

• Cream

Adult midges resemble tiny mosquitoes and generally range from size 18-24. Most commonly, midge adults are:

• Black

• Cream

• Olive

When They're Most Active

• Early morning through late morning.

• Cloudy days and sunny days

• Cooler weather

Top Fly Patterns

1. Hilbert’s Day Saver Midge Size 20-22

2. Easdon’s Blindside Midge Size 20-22

3. Juan’s Pale Ale Midge Size 18-20

Blue Wing Olives (BWOs)

Overview

Blue Wing Olives are one of Colorado's most important mayflies and continue to hatch throughout June, especially on overcast days.

Even when larger insects are present, BWOs remain a staple food source for selective trout.

Life Cycle

Blue Wing Olives follow a three-stage life cycle:

1. Nymph

2. Emerger

3. Dun (Adult)

After hatching, adult insects rest briefly on the water before flying to streamside vegetation where they mature and eventually return to lay eggs.

BWO adults resemble tiny “sail boats” when they emerge onto the water surface and wait for their wings to dry.

What They Look Like

BWO nymphs are:

• Slender

• Olive to brown in color

• Dark wing case

Adults typically feature:

• Olive body

• Gray-blue wings

• Sizes 18-22

Hilbert’s Day Saver May is a guide favorite for targeting trout feeding on bwo nymphs.

When They're Most Active

• Noon to 4:00 PM

• Overcast days

• Light rain

• Cooler afternoons

Top Fly Patterns

1. Hilbert’s Day Saver May BWO size 18-22

2. Hilbert’s Sexi Top May size 18-22

3. Barrs Emerger size 18-20

Pale Morning Duns (PMDs)

Overview

Pale Morning Duns are one of Colorado's premier summer hatches and become increasingly important throughout June.

Large PMD hatches can create some of the most technical and rewarding dry fly fishing of the year.

Trout often become highly selective during PMD activity, feeding heavily on emerging insects and adults trapped in the surface film.

PMD nymphs are often dark in color, when emerging their wing case splits open revealing the light olive or yellow color of the adult (seen here on the top insect)

Life Cycle

PMDs follow the classic mayfly life cycle:

1. Nymph

2. Emerger

3. Dun

4. Spinner

The nymphs spend most of their lives in riffles and moderate currents before emerging and drifting helplessly toward the surface. Trout love to feed on PMD nymphs swimming helplessly towards the surface.

What They Look Like

Nymphs:

• Dark brown

• Tan

• Olive-tan coloration

Adults:

• Pale yellow or amber body

• Cream or grey-colored wings

• Sizes 14-18

Spinner falls often occur during evening hours.

When They're Most Active

• Late morning

• Early afternoon

• Typically 11:00 AM to 3:00 PM

Top Fly Patterns

1. Hilbert’s Day Saver May PMD 18-16

2. Hilbert’s Sexi Top May PMD 18-16

3. Keller’s Ms. Tickle Cripple 18-16

Caddis

Overview

If there is one hatch that defines the beginning of summer in Colorado, it's caddis.

Massive caddis emergences can blanket entire river corridors and produce incredible dry fly fishing. Trout often feed aggressively during these events and can become less selective than during mayfly hatches.

Life Cycle

Caddis undergo a complete metamorphosis:

1. Egg

2. Larva

3. Pupa

4. Adult

The pupal stage is particularly important because caddis pupae swim rapidly toward the surface.

This movement often triggers aggressive feeding behavior from trout.

What They Look Like

Larvae:

• Green

• Tan

• Cream

• Amber

Pupae:

• Bright green

• Olive

• Tan

• Amber

Adults resemble small moths and feature tent-shaped wings.

Most June adult caddis range from:

• Size 14-18

• Tan

• Olive

• Gray

• Brown

When They're Most Active

• Afternoon

• Evening/Night

• Sunny days

Peak activity often occurs from:

• 2:00 PM until after dark

Top Fly Patterns

1. Juan’s Kryptonite Caddis size 16-14

2. Lafontaine’s Sparkle Pupa size 16-14

3. Elk Hair Caddis size 16-14

Golden Stoneflies

Overview

Golden Stoneflies are among the largest aquatic insects trout encounter throughout June.

These insects provide trout with a substantial meal and often trigger ferocious subsurface strikes and explosive surface takes.

Golden Stones become particularly important during runoff conditions due to the active nymphs being washed away in the current.

Life Cycle

Golden Stones have one of the longest life cycles of any aquatic insect.

1. Egg

2. Nymph

3. Adult

Nymphs spend up to three years living among rocks in fast-moving water before crawling onto shore to emerge.

Unlike mayflies and caddis, stoneflies do not emerge directly on the water.

What They Look Like

Nymphs:

• Dark brown

• Amber

• Golden yellow

Adults:

• Bright golden-yellow body

• Long antennae

• Flat wings laying across their back

Sizes typically range from:

• 6-12

When They're Most Active

• Midday

• Afternoon

• Warm sunny days

Adults are often most active along grassy banks and streamside vegetation.

Top Fly Patterns

1. Pats Rubber Legs size 12-8

2. Twenty Incher Stone size 12-8

3. Henry’s Fork Stone size 12-8

Yellow Sallies (Late June)

Overview

Yellow Sallies are smaller cousins of Golden Stoneflies and become increasingly important toward the end of June.

These insects often go overlooked by anglers, but trout feed on them eagerly. Yellow Sallies are clumsy insects and trout love to pounce on an easy meal on the surface.

Life Cycle

Like all stoneflies:

1. Egg

2. Nymph

3. Adult

The nymphs live among rocks and emerge by crawling onto shore before transforming into adults.

Yellow Sallies often resemble a miniature golden stone

What They Look Like

Nymphs:

• Yellow-brown

• Olive-yellow

Adults:

• Bright yellow body

• 4 wings

• Slender profile

Most range from:

• Size 14-18

When They're Most Active

• Afternoon

• Evening

• Warm sunny days

Look for activity around grassy banks and slower water adjacent to riffles.

Top Fly Patterns

1. Iron Sally size 18-14

2. Two Bit Sally size 18-14

3. Galloup’s Butch Sally size 18-14

This sample was taken from a trout on the Eagle River in June. Notice the wide variety of insect species this trout was feeding on. What all do you see?

Putting It All Together

One of the biggest mistakes anglers make in June is focusing on only one hatch.

Successful anglers constantly observe:

• Water temperatures

• Time of day

• Weather conditions

• Insect activity

• Trout feeding behavior

On any given June day, trout may feed on midges in the morning, PMDs during midday, caddis throughout the afternoon, and all three along grassy banks in the evening.

Understanding these transitions is often the difference between a good day and a truly exceptional day on the water.

Learn Colorado Entomology on the Water with a CRO Guide

Reading about insects is a great start, but nothing accelerates your learning faster than spending a day on the river with an experienced Colorado River Outfitters guide.

Our guides spend hundreds of per year on Colorado's rivers studying hatches, observing trout behavior, and helping anglers understand what fish are feeding on and why.

During your trip, we'll teach you:

• How to identify aquatic insects

• How to match the hatch

• How trout feed during different stages of emergence

• Fly selection strategies

• Seasonal hatch timing

• Rigging and presentation techniques

Whether you're a beginner or experienced angler, improving your understanding of entomology will make you a better fly fisher for life.

Ready to take your hatch knowledge to the next level? Give us a call or text at

970-236-1937 or click the button below!

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