Verified for 2026

Maryland Hatch Chart for Fly Fishing (2026)

Last verified: April 2026. Sources: Maryland DNR, Backwater Angler (Hereford, MD), Maryland Fly Fishing reports, plus Cast & Tie observations on the Gunpowder and Savage in 2026.

Maryland holds two trout fisheries that matter at a national level — the Gunpowder Falls tailwater in Baltimore County and the Savage River tailwater in Garrett County. Each runs a different hatch calendar shaped by its release schedule and watershed geology. This chart treats them as two separate columns where they diverge and combines them where they don't.

Season snapshot: Maryland (April 2026)

Water What's hatching Best fly Notes
Gunpowder Falls Hendrickson, BWO, tan caddis, midges Walt's Worm (sub-surface), Hendrickson dun #14 Hendricksons run mid-afternoon on overcast days; BWOs lock in midday
Savage River BWO, blue quill, hendrickson Walt's Worm, Green Weenie sub-surface Cooler water — peak hatches running 1-2 weeks behind Gunpowder

How to read a hatch chart

Hatch dates shift by year, watershed, and water temperature. A "May 15" Sulphur emergence on the Gunpowder might run May 8 in a warm spring or May 22 after a cold April. The dates below represent typical windows under typical conditions — use them to plan your trips, not to pre-commit.

Sizes are given in standard hook-size notation (the larger the number, the smaller the fly). Most Maryland mayfly hatches sit in the 14-18 range. Stages matter: a "dun" is the freshly emerged adult sitting on the surface; a "spinner" is the spent egg-laying form drifting flush; an "emerger" is the nymph breaking the surface tension. Trout often key on a single stage and refuse the others.

Tailwater hatches stretch over longer windows than freestone hatches. The Gunpowder's Sulphur run will produce eaters across six full weeks; a freestone Sulphur hatch might give you eight productive evenings.

Month-by-month hatch chart

January

Insect Size Hours Stage Best fly Notable waters
Midges (multiple species) 22-26 All day All Griffith's gnat, zebra midge Gunpowder, Savage
Little black stoneflies 16-18 Late morning Adult + nymph Black stonefly nymph Gunpowder

February

Insect Size Hours Stage Best fly Notable waters
Midges 22-26 All day All Zebra midge, RS2 Gunpowder, Savage
Little black stoneflies 16-18 Midday Adult Black stonefly Gunpowder
Early black stones 14-16 Afternoon Adult Stimulator (small), black caddis Gunpowder

March

Insect Size Hours Stage Best fly Notable waters
Blue-winged olives (BWO) 18-22 Midday on overcast Dun + emerger BWO parachute, RS2 Gunpowder primarily
Midges 22-26 All day All Zebra midge Gunpowder, Savage
Stoneflies (continued) 16-18 Midday Adult Black stonefly Gunpowder

April

Insect Size Hours Stage Best fly Notable waters
Hendrickson 12-14 Afternoon Dun + spinner Hendrickson parachute, Walt's Worm sub-surface Gunpowder, Savage (later)
Blue quill 16-18 Late morning Dun Blue quill parachute Savage
BWO 18-20 Overcast midday Dun + emerger BWO parachute Both
Tan caddis 14-16 Late afternoon Adult + pupa Elk hair caddis (tan), Green Weenie sub-surface Gunpowder

May

Insect Size Hours Stage Best fly Notable waters
Sulphurs (peak hatch) 14-18 Evening (4 pm-dark) Dun + spinner + emerger Sulphur parachute, sulphur emerger Gunpowder primary
March browns 12-14 Afternoon Dun + spinner March brown parachute Savage
Pale evening duns 16-18 Evening Dun PED parachute Savage
Cinnamon caddis 14-16 Mid-afternoon onward Adult + pupa Tan elk hair caddis, sparkle pupa Gunpowder, Savage
Spotted sedge 14-16 Afternoon-evening Adult Tan elk hair caddis Gunpowder

June

Insect Size Hours Stage Best fly Notable waters
Sulphurs (continued) 14-18 Evening Dun + spinner Sulphur parachute, rusty spinner Gunpowder
Slate drakes / Isonychia 10-12 Late afternoon Dun + nymph Isonychia nymph, slate drake parachute Both
Cinnamon/Spotted caddis 14-16 Afternoon-evening Adult Elk hair caddis Both
Inchworms (terrestrial) 14 All day — Green Weenie Both

July

Insect Size Hours Stage Best fly Notable waters
Cinnamon/Spotted caddis 14-16 Evening Adult Tan elk hair caddis Gunpowder, Savage
Tricos 22-24 Early morning Spinner fall Trico spinner, parachute Gunpowder
Terrestrials 12-16 All day — Ant, beetle, Green Weenie, hopper Both
Sulphurs (sporadic) 16-18 Evening Dun + spinner Sulphur parachute Gunpowder

August

Insect Size Hours Stage Best fly Notable waters
Tricos 22-24 Morning (peak hatch) Spinner fall Trico spinner
Terrestrials (peak) 12-16 All day — Hopper, ant, beetle, Green Weenie Both
Cinnamon caddis (tail end) 14-16 Evening Adult Tan elk hair caddis Gunpowder

September

Insect Size Hours Stage Best fly Notable waters
BWO (return hatch) 18-22 Midday on overcast Dun + emerger BWO parachute, RS2 Both
Slate drakes / Isonychia 10-12 Afternoon Dun + nymph Isonychia nymph
Terrestrials 12-16 All day — Ant, beetle, hopper Both

October

Insect Size Hours Stage Best fly Notable waters
BWO 18-22 Midday Dun + emerger BWO parachute Both
Midges 22-26 All day All Zebra midge, Griffith's gnat Both

November

Insect Size Hours Stage Best fly Notable waters
BWO (tail end) 20-22 Midday on warm overcast Dun + emerger BWO parachute Both
Midges 22-26 All day All Zebra midge Both
Streamer fishing peaks — All day — Streamers, sculpins Both

December

Insect Size Hours Stage Best fly Notable waters
Midges 22-26 Midday All Zebra midge, RS2 Both
Subsurface only — — — Walt's Worm, small nymphs Both

Top 5 most important hatches in Maryland

1. Sulphurs (Gunpowder Falls)

When: Mid-May through end of June. Peak: last 10 days of May. Where: Big Gunpowder Falls catch-and-release section, Hereford to Falls Road. Identification: Pale yellow to creamy yellow body, size 14-18. Three tails. Yellowish-tan wings on the dun. Why it matters: Six weeks of consistent evening dry fly fishing. Wild brown trout key on Sulphurs more reliably than on any other hatch in the state. Best patterns:

  • Sulphur parachute (dun) — primary surface fly
  • Rusty spinner — last 30 minutes of light
  • Sulphur emerger / pheasant tail (size 16) — best 30 minutes before duns appear

Fishing the hatch: Position above productive runs by 4 pm. Watch the air, not the water — the first males will be in the air before any duns are on the surface. Once spinner fall begins (typically last 20 minutes of light), trout switch from duns to spinners and refuse upright patterns.

2. Hendrickson (both rivers)

When: Mid-April to early May. Where: Both Gunpowder and Savage; warmer Gunpowder runs slightly earlier. Identification: Reddish-brown body, slate gray wings. Size 12-14 — large for an Eastern mayfly hatch. Why it matters: First major mayfly hatch of the year. Trout that have been eating midges and stoneflies all winter become aggressive surface feeders for two weeks. Best patterns:

  • Hendrickson parachute (dun)
  • Red quill spinner
  • Pheasant tail (size 14) — sub-surface emerger

Fishing the hatch: 1 pm-4 pm window most productive. Look for risers in slow tailouts and pool heads. Spinners drop the following morning if you can be on the water at 9-10 am.

3. Blue-Winged Olives (year-round)

When: Three windows — March-April, September-November, sporadic on overcast days year-round. Where: Both rivers. Identification: Small (size 18-22), dark olive body, blue-gray wings. Multiple species under the BWO umbrella. Why it matters: The most reliable cool-weather dry fly hatch. When nothing else is happening, an overcast 50-degree day produces BWOs. Best patterns:

  • BWO parachute (size 18-20)
  • RS2 (size 20-22) — emerger
  • WD-40

Fishing the hatch: Cloudy days, 11 am-3 pm. Trout sip duns in soft water; longer drifts and slack-line casts beat short tight casts.

4. Cinnamon and Spotted Caddis (Gunpowder primarily)

When: Mid-May through end of August. Where: Big Gunpowder Falls, primarily mid-river through lower river. Identification: Tan-cinnamon to grayish-brown wings, size 14-16. Active flutterers across the surface. Why it matters: Three full months of evening dry-fly opportunity, often overlapping with Sulphurs in early summer and providing the entire show in July-August. Best patterns:

  • Tan elk hair caddis (sizes 14-16)
  • Sparkle pupa (sub-surface, before adults appear)
  • X-caddis (riding low for finicky fish)

Fishing the hatch: Late afternoon through dark. The Gunpowder's tree-shaded character makes it dim early — trout key on caddis from 6 pm onward in midsummer.

5. Midges (year-round, but critical December-March)

When: Year-round; the only consistent surface activity from December through early March. Where: Both rivers, but Gunpowder more reliable due to consistent thermal release. Identification: Tiny — sizes 22-28. Black, gray, cream, and red color phases. Why it matters: Winter trout fishing in Maryland is a midge fishery. Anglers who can't fish small flies on light tippet are limited to streamers in the cold months. Best patterns:

  • Zebra midge (sub-surface, beadhead)
  • Griffith's gnat (cluster surface fly)
  • RS2 (emerger)

Fishing the hatch: Midday warm-up window, 11 am-2 pm. 6X tippet minimum. Long leaders (12 ft+) help with drag-free drifts on small flies.

Cold-water vs warm-water hatch differences

The Gunpowder runs cold year-round (typical 50-58°F summer release) and consequently extends every hatch window relative to a typical Maryland freestone. A Sulphur hatch that runs three weeks on a warm freestone runs six weeks on the Gunpowder. The Savage runs even colder (45-55°F) and shifts every hatch 1-2 weeks later than the Gunpowder.

Limestone-influenced waters in Maryland (small spring creeks in Frederick County and the Hagerstown valley) hatch closer to a Pennsylvania limestone calendar — Sulphurs running mid-May, scuds and sowbugs available year-round.

Freestone Maryland streams (Patapsco, Patuxent, smaller mountain streams in Western MD) follow a more conventional Eastern hatch calendar, with hatches roughly 2-3 weeks behind PA freestones at similar elevation.

Sources and verification

This chart cross-references:

Where to fish each hatch

Patterns for Maryland hatches

  • Walt's Worm — covers BWO, Hendrickson, and caddis sub-surface across the full season
  • Green Weenie — June terrestrial peak and early-summer attractor work
  • Mop Fly — heavy point fly for high-water windows in spring runoff

Last verified: April 2026. Updated quarterly. Next scheduled review: July 2026.