Pale morning dun
Also called PMD, Pale Morning Duns
A “Pale Morning Dun” (PMD) is a common mayfly hatch made up of small, pale yellow mayflies. Anglers use PMD nymph, emerger, dun, and spinner patterns to match it.
- Group
- Mayfly hatches
- Category
- Entomology & forage
- Level
- Beginner
- Water
- Freshwater
Last updated
What Pale morning dun means
On many Western trout rivers, “PMD” is the shorthand for pale, yellow mayflies in the genus *Ephemerella* (often *Drunella* in older references). The adults are light-colored duns, and the hatch can bring steady surface feeding when it lines up.
On the water, PMD usually means matching a stage, not just a color. Before adults show, trout often key on nymphs and emergers. During the hatch they may take duns in the film, and later they can switch to spent spinners lying flat on the surface.
Because common names get used loosely, “PMD” can mean slightly different bugs depending on the river. The practical move is to look at what’s in the air and on the water, then pick the closest nymph/emerger/dun/spinner profile in a pale yellow range.
Why it matters on the water
PMD hatches are a good place to learn the difference between “trout are rising” and “trout are eating adults.” If fish are bulging or porpoising, an emerger or cripple profile often outperforms a high-floating dun pattern. If rises are clean sips, a dun or spinner match is usually closer.
PMDs can overlap with other light-colored mayflies, especially Sulphur-type hatches in some regions. Knowing that “PMD” is a hatch category, not a single insect, keeps the focus on what the trout are actually selecting—size, silhouette, and stage—before swapping through random yellow dries.
Shop Pale morning dun
Read next
- CrippleA cripple is an adult insect imitation tied to look stuck mid-hatch, with a shuck, splayed wing, or a low-riding body that can’t fully take off.
- Pheasant Tail NymphA slim, buggy nymph pattern tied with pheasant tail fibers, usually to imitate mayfly nymphs. It’s a standard “search” nymph for trout and other freshwater fish.
- SpinnerA spinner is a dry fly that imitates an adult mayfly after it has mated and fallen spent on the water, usually with wings laid flat to the sides.
- Sulphur“Sulphur” is a common hatch label for small yellow mayflies, most often in the genus Ephemerella. Anglers use it to match pale yellow duns and their evening spinner falls on many trout rivers.