Fly fishing hatch timing
Hatch calendars for the top 50 Eastern US trout rivers.
Month-by-month timing for every major hatch — Sulphurs, Green Drakes, Hendricksons, BWOs, October Caddis, Trico spinner falls — across the states we cover. Each calendar lists peak windows, fly patterns, water temperature triggers, and time of day.
A note on hatch timing
Hatches respond to water temperature, not the calendar. A cold spring can push everything back two weeks; a warm spell can collapse two hatches into one. Cross-reference with a local fly shop before planning a trip.
What's hatching now
August on the water.
Top eight rivers right now by aggregate hatch intensity.
Pennsylvania
Upper Delaware River
- Midgeheavy
- Pale Morning Dunheavy
New York
West Branch Delaware River
- Midgeheavy
- Pale Morning Dunheavy
Tennessee
South Holston River
- Midgeheavy
- Sulphurheavy
Virginia
Jackson River
- Midgeheavy
- Pale Morning Dunheavy
North Carolina
Nantahala River
- Midgeheavy
- Pale Morning Dunheavy
North Carolina
Watauga River (NC)
- Midgeheavy
- Pale Morning Dunheavy
Tennessee
Watauga River (TN)
- Midgeheavy
- Pale Morning Dunheavy
Tennessee
Clinch River
- Midgeheavy
- Pale Morning Dunheavy
Hatch types
- Mayfly
- Caddis
- Stonefly
- Midge
- Terrestrial
18 species tracked across five hatch types, with peak windows and water-temperature triggers.