Finding the right pmd dry fly pattern can feel like a bit of a rabbit hole when you're staring at a box full of yellow duns. We've all been there—standing knee-deep in a riffle, watching fish rise all around us, while we frantically cycle through every size 16 and 18 yellow fly we own. Pale Morning Duns (PMDs) are arguably the most important hatch of the summer for many fly fishers, especially across the West, and having a fly that actually mimics their profile is the difference between a frustrating morning and a banner day.
The thing about PMDs is that they aren't just "one" color. Depending on the river, the time of day, or even the temperature, they can range from a bright sulfur yellow to a creamy tan or even a subtle, pale olive. Because of that, your pmd dry fly pattern needs to be more than just a yellow hook with wings. It needs to sit in the water correctly and match the specific stage of the hatch that the trout are keyed in on.
Understanding the PMD Silhouette
When you're looking at a pmd dry fly pattern, the first thing you should think about is the silhouette. Trout are surprisingly picky about how a bug sits on the surface film. If the fish are taking duns—the fully hatched adults—they're looking for those upright, sailboat-like wings. However, a lot of times, the trout are actually picking off the emergers or "cripples" that are stuck in the surface tension.
If you only carry one type of fly, you're going to miss out. I like to carry a mix of high-floating parachutes and low-riding sparkle duns. The parachute versions are great for faster water or riffles where you need to see your fly easily. But if you're fishing a glassy flat or a slow pool, a sparkle dun or a CDC-winged pattern is usually the way to go. These sit lower in the film and look a lot more natural to a trout that has all day to inspect your offering.
Why Color and Size Matter More Than You Think
It's easy to get caught up in the "yellow" aspect, but PMDs are actually quite delicate in their coloration. Most people tie or buy them in a size 16 or 18, which is the standard. However, early in the season, the bugs tend to be a bit larger, while by late August, you might need to drop down to a size 20 or even 22 on some technical tailwaters.
As for the color, I've found that a "PMD tan" often works better than a bright, neon yellow. If your pmd dry fly pattern is too bright, it might look like a beacon of light on the water, which can actually spook wary fish. Natural dubbing—like beaver or a fine dry fly synthetic—that has a bit of translucency is usually the best bet. When that dubbing gets wet, it takes on a life of its own and mimics the actual body of the insect much better than a solid, opaque thread.
The Power of CDC
If you haven't started using CDC (Cul de Canard) in your pmd dry fly pattern, you're missing a trick. CDC is incredibly buoyant because of the natural oils, but more importantly, it has a movement and a "breathability" that synthetic materials just can't match. A simple CDC Transition Dun is one of my favorite patterns. It's basically just a tail of shuck material, a dubbed body, and a small clump of CDC tied in as a wing.
The beauty of this pattern is its simplicity. It doesn't have a heavy hackle, so it sits right in the surface film. When the light hits those CDC fibers, it creates a bit of a halo effect that mimics the fluttering wings of a struggling insect. It's a killer during the peak of the hatch when the fish are being particularly "snotty" about what they'll eat.
Tying Your Own PMD Patterns
For the folks who sit at the vise, tying a pmd dry fly pattern is a great exercise in proportion. Since these are smaller flies, it's really easy to over-bulk the hook. You want a slim, tapered body and a wing that isn't twice as long as the hook shank.
Materials you'll want to have on hand: * Hooks: Standard dry fly hooks or slightly short-shanked hooks for a truer profile. * Thread: 8/0 or 12/0 in a light yellow or cream. * Tail: Coq de Leon or synthetic micro-fibetts. * Body: Fine dry fly dubbing in PMD yellow, tan, or light olive. * Wing: Turkey flats, CDC, or white poly-yarn for visibility. * Hackle: High-quality dry fly hackle in light ginger or dun.
One tip I've learned over the years: try tying a few with a "hot spot" near the head. Just a tiny wrap of orange or pink thread right behind the eye can sometimes act as a trigger point. I don't know why it works, but on some days, it's the only thing they'll take.
Tactics for Fishing the Hatch
Once you have your pmd dry fly pattern ready, you have to present it correctly. PMDs usually hatch from mid-morning to early afternoon. It's a gentleman's hatch—you don't have to be out there at the crack of dawn, which is a nice change of pace.
The key is a drag-free drift. Because these bugs are small, even the tiniest bit of micro-drag will make your fly look like a motorboat crossing the current. Use a long leader—12 feet isn't overkill on clear water—and a light tippet, like 6X. If you're seeing fish rise but they're refusing your dun pattern, it's time to switch to a "cripple" or a "spinner."
Don't Forget the Spinner Fall
The spinner fall is the often-overlooked finale of the PMD cycle. After the adults have mated, they return to the water to lay their eggs and then die. These "spent" bugs have their wings spread out flat on the water. A spinner-style pmd dry fly pattern usually features clear or white wings made of Z-Lon or organza, tied horizontally.
Fishermen often pack up and head for lunch right when the spinner fall is starting. If you see fish rising in a very rhythmic, slow way, they're probably sipping spent spinners. It's some of the most technical and rewarding fishing you can do. You'll need a fly that lies perfectly flat and a cast that puts the fly exactly in the "feeding lane" of the fish.
Reading the Water and the Fish
When you're on the river during a PMD hatch, pay attention to where the fish are holding. In the early stages of the hatch, they'll often be in the faster riffles, grabbing the nymphs as they rise to the surface. As more duns begin to pop, the fish will move into the slower "buckets" and tailouts.
If you see a lot of "flash" under the water but no actual breaks on the surface, the trout are likely eating emergers just a few inches down. In that case, you might want to grease your leader but leave the last few inches of tippet dry so your pmd dry fly pattern sits just barely under the surface. It's a subtle shift, but it makes a massive difference.
Final Thoughts on the PMD
At the end of the day, the pmd dry fly pattern you choose should be one you have confidence in. Whether it's a classic Sparkle Dun or a fancy CDC Thorax Dun, the most important thing is that it matches the size and behavior of the bugs on the water. Keep a variety of shades and styles in your box, because trout can change their minds in a heartbeat.
Next time you see those little yellow sailboats drifting down the river, don't just grab the first yellow fly you see. Take a second to look at what the fish are actually doing. Are they head-and-tailing? Are they just poking their noses up? Once you figure out that puzzle, you can pick the right pattern and have a day you'll be talking about for the rest of the season. Happy fishing!