Top 12 Pale Morning Dun (PMD) Flies & How to Fish the Hatch

Updated November 5th, 2026

At a Glance:

• Best nymphs: TNT Jig, Crackback PMD and Pheasant Tail
• Best emergers and cripples: PMD Sprout, PMD CDC Emerger, Captive Dun, Film Critic and Last Chance Cripple
• Best duns and spinners: Sparkle Dun, Rusty Spinner, CDC Parachute Spinner and CDC Biot Comparadun
• Hook size: 14–20, most often 16 (14–16 early in the season, 16–18 later)
• When: late May through early October, peaking in June and July
• Time of day: late morning to afternoon for duns; spinners at first light and in the evening
• Where: rivers and spring creeks across the West, with the longest seasons on tailwaters

When it comes to hatches, reliability is everything. Every year, anglers travel to the West or head to their local river hoping to time famous hatches like the green drake or salmonfly, only to arrive a few days early or at the tail end of the party.

These hatches are some of the most exciting anywhere: massive stoneflies marching up river rock to dry their wings before taking flight, or big drakes floating downstream like an armada of tiny sailboats. Fish (and fishermen) go nuts for them, but their emergence is short-lived, sporadic and hard to pin down. That's not the case for the pale morning dun (PMD), one of the most reliable, abundant and widespread hatches of the year, and a favorite of many western anglers.

What is a pale morning dun?

A pale morning dun is a small western mayfly with a pale yellow to light olive body, light dun-gray wings and three tails. "PMD" covers two closely related species whose hatches overlap through the warmer months. The first, Ephemerella dorothea infrequens, hatches earlier and runs larger, about size 14–16. As it tapers off, Ephemerella excrucians takes over, running smaller, about 16–18 and sometimes down to 20, and often lasting into fall. PMDs as large as 12 or as small as 20 do turn up, but a 16 is your all-around sweet spot. The same patterns work for both species, but size absolutely matters.

After their final molt, PMD spinners turn rusty to olive-brown with clear wings. Trout eat every stage: nymph, emerger, dun and spinner.

The PMD life cycle

Step through each stage below to see where it lives in the river, how long it lasts and when trout eat it.

When do PMDs Hatch?

The first PMDs can arrive as early as late May, peak in June and July, and taper off as fall approaches. Hatches range from a trickle to blanket hatches so thick they're nearly impossible to fish because of the sheer volume of bugs.

Generally, cool, overcast weather makes for a better hatch. PMDs do hatch on warm bluebird days, but those hatches are lighter and shorter. On a hot day, expect the hatch to start before lunch; in cool, cloudy weather it pushes into the afternoon and usually runs longer and thicker.

It's common to find trout eating spinners from first light into the morning, and again in the late afternoon and evening. After their final molt, male spinners gather in swarms over riffles, usually on calm mornings and evenings, and females fly into the swarm to mate in flight. The males soon fall spent to the water, while the females return to the riffles to release their eggs at the surface before falling spent themselves. Either way, it isn’t long before their bodies are easy targets for sipping trout.

River conditions play a big role in how long and heavy PMD hatches are. The steady temperatures of a tailwater favor a long hatch season, while hot days or low water on a freestone river cut hatches short.

How do you fish a PMD hatch?

Nymph before and during the hatch. Don't overlook nymphs. As they move toward emergence, PMD nymphs swim from the riverbed to the surface. Nymphing is often more productive than fishing the duns.

Read the rise, or the lack of one. If you see trout flashing as they move in and out of a feeding lane, or a white mouth opening near the bottom while duns float by untouched, think nymphs or emergers.

Start with an emerger when the duns are ignored. It's common for trout to key on emerging PMDs and cripples instead of duns, refusing a dry that drifts perfectly over their nose. PMDs are slow to emerge, which makes that stage easy pickings. If fish are rising but you don't see duns on the surface, or they're ignoring the duns in a big hatch, start with an emerger.

Pick one fish and time your cast. The water may be boiling with rising fish, but it's better to choose one and put your fly in its feeding lane. With lots of bugs on the water, trout won't move out of their way for your imitation. Like a metronome, a feeding trout settles into a rhythm, and timing your cast to it can make the difference. Start at the back of the pod and work your way up so you don't put down the rest of the fish.

Stay for the spinner fall. Carry spinners for early mornings and evenings, when the spent flies collect on the water and trout sip them steadily.

Top PMD Nymphs

1. TNT Jig

The TNT Jig is an excellent searching fly that we reach for before a hatch starts or early in the season. It has a great profile when wet, and its small hot spot tail and yellow dubbed thorax make it a convincing PMD nymph. Fish it as a dropper beneath an unweighted nymph, emerger or soft hackle to find which part of the water column trout are feeding in.

Best for: searching the water column before the hatch starts. Shop the TNT Jig.

2. Crackback PMD

A super buggy nymph, the Crackback comes in weighted and unweighted versions. As the name suggests, its wing case is "cracked," imitating a PMD just beginning to emerge.

Best for: trout feeding below the surface at the start of a hatch and during it. Shop the Crackback PMD.

3. Pheasant Tail

Some flies aren't going anywhere, and we'd be remiss not to mention the pheasant tail. A standard beadhead pheasant tail gets it done during most mayfly hatches, as long as the size is right and the drift is drag-free. A soft hackle pheasant tail imitates an emerging PMD, so carry some of each, weighted and unweighted. Try an unweighted pheasant tail as your point fly with a Crackback, TNT Jig or weighted pheasant tail as the dropper.

When all else fails, treat an unweighted pheasant tail with the lightest touch of floatant. It will ride in the surface film like a PMD trying, or failing, to emerge. If you can't track it, set the hook whenever you see a rise near your fly.

Best for: any stage of the hatch, from the riverbed to the surface film. Shop the Beadhead Pheasant Tail or the Soft Hackle Pheasant Tail.

The Best PMD Emergers and Cripples

Emerging bugs and cripples take very little effort for a trout to eat, and a trailing shuck or a half-open wing is a trigger. These five ride in or just under the film. Shop all emergers and cripples.

4. PMD Sprout

The Sprout is a killer mayfly emerger that also comes in BWO, Callibaetis and Trico versions. Most of the fly rides below the surface, including an Antron shuck and a lightly dressed body, while the hackle sits level with the surface film around a white foam post. That post makes it easier to see than most emergers without spoiling the emerger profile, and it keeps the fly from drowning in riffles.

Best for: fishing an emerger in riffles and faster water, where you need to see it. Shop the PMD Sprout.

5. PMD CDC Emerger

CDC is the gift that keeps on giving, one of the most naturally buoyant and buggy materials there is. Leave the CDC wing untreated so it floats while the body and trailing shuck hang below the film. If you're having trouble seeing it, add a little floatant to the wing. If it drowns, dry the CDC by rubbing it between your fingers or against your palm, or use a Fly Banjo to "ping" the fly and shake off the water.

Best for: a low-riding emerger for trout sipping just under the film. Shop the PMD CDC Emerger.

6. Captive Dun

A Rene Harrop classic, this is a fly every angler should carry for a PMD hatch. The tail is usually mallard flank with a few Antron fibers to suggest a shuck, but the CDC loop wing is what seals the deal for picky fish, imitating the wings of a PMD in the last stage of becoming a dun. Its small profile can be hard to track, so fish it as a trailer behind a more visible dry if you are struggling.

Best for: picky fish eating duns that haven't quite broken free. Shop the Captive Dun.

7. PMD Film Critic

A pattern by the legendary Bob Quigley, the Film Critic is a home run of an emerger. Like the Sprout, its tail and body hang below the surface, but sparse, stacked hackle lets it ride a touch lower than a traditional parachute. A prominent wing at the hook eye makes it easy to see.

Best for: slick, slow spring creeks where trout can inspect every detail. Shop the PMD Film Critic.

8. Last Chance Cripple

Another Rene Harrop staple, the Last Chance is one of the most effective mayfly cripples ever tied. Like many Harrop patterns, it uses a biot body for realistic segmentation. A sparse shuck, a slender profile, a CDC wing and a few turns of hackle make it land softly and float well.

Best for: selective trout eating cripples, in both soft water and heavier currents. Shop the Last Chance Cripple PMD.

The Best PMD Dry Flies & Spinners

There are a lot of good options, but these are some tried-and-true patterns that have been working for decades.

The key for targeting rising fish during a PMD hatch is to pick your fish and time your cast. While the water may be boiling with rising fish and you feel you can just pitch it in there, its better to choose a fish and put the fly in its fishing lane. If there are a lot of bugs on the water, the trout are not going to move out of their way to take a risk on your imitation. Secondly, similar to a metronome, trout will find a feeding rhythm, and timing your presentation can make the difference between success and frustration. Start with the back of the pod and work your way up so you don't put down those happy fish!

+ Dry Fly Fishing: What, When, and Where

9. Sparkle Dun

One of the first PMD dry flies you should reach for, the Sparkle Dun has brought many thousands of trout to hand and is one of the best all-around mayfly patterns ever tied. Craig Mathews and John Juracek of West Yellowstone developed it in the mid-1980s for slow, technical water, and it quickly became a favorite everywhere. Somewhere between emerger and dun, its Z-Lon shuck imitates the last stage of emergence, and the splayed deer hair wing gives a great profile and good visibility while riding low.

Best for: the first dry to tie on when trout are eating duns. Shop the Sparkle Dun PMD.

10. Rusty Spinner

The rusty spinner is a must-have if you plan to fish every phase of the hatch or get on the water late in the evening. After PMDs mate, the spinners fall to the river with their wings spread flat, and trout quickly take notice. Profile and size are key, and the rusty spinner's tails, slender body and splayed poly wings match them well.

Most spinners fall in the evening or early morning, so tracking your fly can be hard, especially in a heavy fall. The Hi-Vis Spinner adds a bright post to help you pick out your fly in low light.

Best for: morning and evening spinner falls. Shop the Rusty Spinner or the Hi-Vis Rusty Spinner.

11. CDC Parachute Spinner

The CDC Parachute Spinner is a great alternative to the traditional rusty spinner and a favorite of many anglers. It lands incredibly lightly and rides flush in the surface film on a sparse parachute hackle. The CDC post makes it easier to track than a traditional spinner and adds natural buoyancy.

Best for: spinner falls on spring creeks and slack water. Shop the CDC Parachute Spinner.

12. CDC Biot Comparadun

The CDC Biot Comparadun is a modern take on the classic Comparadun. It swaps the original's dubbed body and deer hair wing for a biot body and a CDC wing. The result is a realistic profile that lands softly and rides flush with the surface.

Best for: super picky fish in slick, glassy water. Shop the CDC Biot Comparadun.

Next time you're on the water and the pale morning duns start hatching, we hope these tips and flies bring you success. If you're in Southwest Montana, stop by the Yellow Dog Fly Shop for all your fly and gear needs. Shop all PMD flies.

Frequently Asked Questions

When do pale morning duns hatch? PMDs hatch from late May through early October across the West, with the heaviest hatches in June and July. Tailwaters often have the longest PMD seasons because their water temperatures stay steady.

What size are PMD flies? Most PMDs match a size 16 hook. Early-season PMDs run larger, about 14 to 16, and later ones run smaller, about 16 to 18, with some as small as 20.

What color are pale morning duns? Duns have pale yellow to light olive bodies and light gray wings. After their final molt, spinners turn rusty to olive-brown with clear wings, so carry rusty spinner patterns for the spinner fall.

What time of day do PMDs hatch? Duns usually hatch from late morning into the afternoon. Hot, sunny days bring earlier, shorter hatches, while cool, cloudy days push the hatch later and make it heavier. Spinners fall at first light and again in the evening.

What is the best fly for a PMD hatch? There isn't one best fly, because trout eat every stage. Carry a nymph such as a Pheasant Tail or Crackback, an emerger such as the Film Critic or Sprout, a Sparkle Dun for the duns and a Rusty Spinner for the spinner fall.

Why are trout refusing my PMD dry fly? Trout often eat emerging or crippled PMDs just under the surface instead of duns on top. If fish are rising but ignoring your dun, switch to an emerger or cripple before you change size or color.

What is a PMD spinner fall? After their final molt, males swarm over riffles and mate with females in flight. Males fall spent to the water first, and females follow after releasing their eggs at the surface. Trout sip them steadily, usually at first light and in the evening, and a rusty spinner is the fly to match them.

Should I nymph before a PMD hatch? Yes. In the hours before a hatch, PMD nymphs become restless and drift more freely in the current, putting a lot of them in front of trout. A Pheasant Tail, TNT Jig or Crackback is often more productive than a dry fly until the duns appear.

Related Articles:

Emergers and Cripples: Techniques, Patterns, and When to Use Them Top 12 Blue-Winged Olive (BWO) Flies and How to Fish the Hatch Top 9 Mother’s Day Caddis Flies and How to Fish the Hatch Montana Fly Fishing Hatches Made Simple Beyond the Salmonfly: 6 Other Montana Fly Fishing Hatches Golden Stonefly Hatch: Timing, Tactics and Top Flies The Top 8 Hopper Flies Fly Fishing for Trout: What Makes a Great Grasshopper Pattern The Top Attractor Dry Flies The Top Streamers for Trout