Free Resource · Updated 2026
The complete fly hatch chart for New York's historic Catskill rivers — the birthplace of American dry fly fishing. From the Beaverkill and Willowemoc to the West Branch and East Branch Delaware, the freestone Esopus Creek and Schoharie Creek, the Adirondack Ausable River, and the storied Battenkill — select your river below for peak hatch timing, fly pattern recommendations, and current month highlights for 2026.
New York Hatch Calendar — Quick Reference
Identifying the hatch is vital, but most days require versatile patterns that trigger strikes even when the water looks quiet. For a curated list of high-percentage patterns that belong in your box year-round, see our guide to the best trout flies in New York, featuring our top 5 essential picks for these waters.
New York Streams
Beaverkill · Willowemoc · Esopus · Schoharie
The birthplace of American dry fly fishing — these freestone streams shaped the Catskill tradition and the legendary patterns still used today. Hatches track air temps closely, with Quill Gordons and Hendricksons arriving in April, Green Drakes and March Browns in May and June. Flows can rise quickly after rain; the best Catskill fishing happens when water clears and drops to fishable levels.
West Branch · East Branch · Main Stem Delaware
Wide, productive rivers with both tailwater and freestone character. The West Branch below Cannonsville Reservoir stays cold year-round, extending the Sulphur and PMD seasons well into summer and keeping fish active during heat events. The Delaware system produces notoriously technical, selective fish — bring long leaders and precise presentations. Green Drakes and Isonychia are highlights of the fall season.
Ausable River (West Branch) · Battenkill River
High-elevation Adirondack and Green Mountain rivers that run colder and clearer than the Catskills. Hatches arrive later in spring due to elevation but persist later into fall — the Ausable West Branch fishes BWOs and Hendricksons through October and November. The Battenkill on the Vermont border is famous for selective wild browns and technical dry fly fishing across a classic spring-fed meadow setting.
The Why Behind the Chart
Epeorus pleuralis
The iconic Catskill hatch that signals the start of the dry fly season. The Quill Gordon fires on early April afternoons when water temps climb into the low 40s°F, drawing trout to the surface for the first time all year. Theodore Gordon developed his famous Quill Gordon dry fly to imitate this very hatch on the Beaverkill and Willowemoc — the pattern remains a Catskill classic. Fish it in the early afternoon and be prepared for a short, intense window of rising fish.
Recommended: #14 Quill Gordon Dry, Comparadun, A.P. Nymph
Ephemerella subvaria
The most dependable mayfly of the early Catskill season, hatching in the afternoon from mid-April through May across all the major NY rivers. Both male (Hendrickson) and female (Red Quill) duns hatch together — carry both patterns. Esopus Creek and the Beaverkill are famous for dense Hendrickson hatches. Trout that have been deep all winter come up aggressively, making this one of the most exciting hatches of the year despite the still-cold conditions.
Recommended: #12–14 Hendrickson Dry, Red Quill, Pheasant Tail Nymph
Ephemera guttulata
One of the most celebrated hatches in eastern fly fishing, firing at dusk on the Beaverkill, Delaware, and Esopus in late May and early June. Large, creamy mayflies blanket the water as the sun sets, triggering surface-feeding frenzies from wild brown trout that rarely show themselves at other times. The Coffin Fly spinner fall after dark can be even more productive than the dun hatch. The West Branch Delaware often peaks a few days behind the Beaverkill due to tailwater temperature moderation.
Recommended: #10 Green Drake Comparadun, Coffin Fly spinner
Ephemerella dorothea
New York's most reliable and longest-running evening hatch, beginning in late May on the Delaware system and Beaverkill and running through July. The hatch fires around 7pm and intensifies at dusk — look for rising fish in the tail-outs and slow glides. On the West Branch Delaware, the tailwater character keeps Sulphur fishing excellent through mid-July when freestone streams have warmed and dropped. Trout on the Delaware can be highly selective during heavy Sulphur falls.
Recommended: #16–18 Sulphur Parachute, Sparkle Dun, CDC Dun
Isonychia bicolor
The Mahogany Dun — one of the finest fall hatches on New York rivers and a welcome return to dry fly fishing after the dog days of summer. Isonychias hatch throughout the day on overcast fall afternoons, producing some of the most consistent surface feeding of the entire season. The Delaware system and Beaverkill are excellent for this hatch. Fish are in prime condition after summer feeding, and the foliage backdrop of October in the Catskills makes this hatch season particularly memorable.
Recommended: #12–14 Mahogany Dun, Isonychia Parachute, Leadwing Coachman Wet
Baetis sp.
New York's most versatile hatch — present on every river, spring and fall, and most reliable on overcast, drizzly days when the clouds keep the fish from looking up. BWOs emerge in two seasonal windows: late March through May and again September through November. The West Branch Delaware's tailwater character keeps BWOs active even into late November. When the weather looks bad, think BWO — Catskill trout have learned to key on this hatch during low-light conditions.
Recommended: #18–22 CDC Dun, Sparkle Dun, RS2 emerger
The Catskill Mountains are the spiritual home of American fly fishing, where legends like Theodore Gordon developed the dry fly patterns still used today. The hatch season opens with the iconic Quill Gordon in early April — often the first dry fly hatch of the year — followed quickly by the Hendrickson, March Brown, and American March Brown. These early hatches on the Beaverkill and Willowemoc define the Catskill tradition and draw serious dry fly anglers every spring.
June brings the celebrated Green Drake hatch to the Beaverkill, Esopus, and Delaware system — one of the most significant hatch events in eastern fly fishing. Sulphurs overlap and extend the evening dry fly season through July, when Trico spinner falls take over on slower meadow sections. The West Branch Delaware's tailwater character provides exceptional PMD and Sulphur fishing all summer, with fish that are notoriously selective and technical.
Fall returns Blue-Winged Olives to the surface through October and November, and Isonychia (Mahogany Dun) provides excellent dry fly action on overcast fall afternoons on the Delaware and Beaverkill. The Adirondack Ausable River fishes later into fall than the Catskill streams. Use FlyFishFinder to track live flows on the Delaware system and time your Catskill trips perfectly.
See Live New York River Conditions →Common Questions
The Quill Gordon typically hatches in early-to-mid April on the Beaverkill and Willowemoc, often the first major dry fly hatch of the season. It fires in the afternoon when water temps reach the low-to-mid 40s°F. Timing can shift by a week or two depending on spring warmth — expect mid-April in average years.
May is New York's richest month for hatches. Carry Hendrickson Comparaduns (#12–14), March Brown Parachutes (#10–12), and Sulphur Sparkle Duns (#16–18). A Green Drake Comparadun (#10) becomes essential late in the month on the Beaverkill and Delaware. Elk Hair Caddis covers you between hatches.
Green Drakes (Ephemera guttulata) hatch in late May through early June, firing at dusk when water temps reach 55–62°F. The Beaverkill and West Branch Delaware are the most famous locations. The Delaware branches often peak a few days later than the Beaverkill due to the tailwater influence moderating temperatures.
The West Branch Delaware is a tailwater fed by Cannonsville Reservoir, providing cold, stable flows year-round. This extends the Sulphur and PMD season into summer and keeps the river fishable during heat waves. The Beaverkill is a freestone stream, so hatches track air temps more closely and the river can warm and drop significantly by August.
The Ausable West Branch fishes Hendricksons and BWOs in spring (April–May), followed by heavy Caddis and Green Drake hatches in June. Summer brings Hoppers and PMDs through August. Fall BWOs extend the season into October and November — later than most Catskill streams due to the Adirondack elevation and cooler temperatures.
May and early June are peak season — Hendricksons, March Browns, Green Drakes, and Sulphurs overlap on the Catskill rivers for a remarkable few weeks. April brings the first Quill Gordons. Fall (September–October) offers excellent BWO and Isonychia fishing on the Delaware system with fewer crowds and stunning foliage.
FlyFishFinder combines hatch knowledge with live gauge alerts, Prime condition indicators, and real angler intel — so you show up on the right day, not the wrong one.
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