Free Resource · Updated 2026
The complete fly hatch chart for Vermont's wild brook trout headwaters, Green Mountains freestone rivers, and the legendary Battenkill. From the Hendrickson hatch on the Battenkill to the White River, Winooski, Mad River, and Lamoille — select your stream below for peak hatch timing, fly pattern recommendations, and current month highlights for 2026.
Vermont 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 Vermont, featuring our top 5 essential picks for these waters.
Vermont Streams
Mad River · Dog River · Nulhegan River · Black River
Cold, high-gradient streams draining the Green Mountains push hatch timing 1–2 weeks later than lower-elevation valley rivers. The Hendrickson may not fire until mid-May on mountain streams, while the Nulhegan's remote Northeast Kingdom headwaters hold wild brook trout that rarely see a fly. These streams run clear quickly after rain and fish best once spring flows moderate in mid-May. Expect hatches to be sparse but the fishing to be intimate and rewarding.
White River · Winooski · Lamoille · Missisquoi
Larger river systems draining Vermont's valleys hold a diverse mix of brown trout, rainbow trout, and brook trout. Hatch timing is earlier than mountain streams and more predictable — the Winooski and Lamoille can see Quill Gordons by late April. The White River is Vermont's most versatile freestone river, with excellent Hendrickson, Green Drake, and Isonychia hatches spread across its main stem and branches throughout the season.
Battenkill · West River
Vermont's most storied waters benefit from groundwater springs and a more moderate temperature regime that supports consistent hatch activity across a long season. The Battenkill — home of Orvis — is famous for its selective wild brown trout and demanding dry fly fishing. Spring hatches arrive earlier, summer hatches (Trico, Sulphur) are more sustained, and fall BWO fishing extends well into October. Expect difficult fish and demanding presentations on both rivers.
The Why Behind the Chart
Epeorus pleuralis
Vermont's opening act of the dry fly season. Quill Gordons fire on the warmest afternoons of late April when water temps climb into the mid-to-upper 40s°F — typically between 2–4pm on sunny days. On lower-elevation rivers like the Battenkill the hatch can arrive in the third week of April; on Green Mountains streams it often waits until early May. The dun rides the current low in the film with wings upright, and trout key on them immediately in riffles and runs. An underrated hatch that signals spring has truly arrived.
Recommended: #12–14 Quill Gordon Dry, Hare's Ear Nymph
Ephemerella subvaria
Vermont's signature spring hatch and the most celebrated event on the Battenkill each year. The Hendrickson hatch transforms even wary wild browns into active, surface-feeding fish. It fires in the early-to-mid afternoon on overcast days when water temps are in the low-to-mid 50s°F — ideal conditions are cool, cloudy, and calm. On the Battenkill it typically peaks in early May; on higher-elevation Green Mountains streams it may push to mid-May. Fish the dun drag-free over rising fish in the flat water sections and smooth runs for the best results.
Recommended: #12–14 Hendrickson Comparadun, A.P. Nymph
Ephemera guttulata
Vermont's most spectacular hatch and the highlight of the June dry fly calendar. Green Drakes emerge at dusk when water temps are in the 55–62°F range, typically in early to mid-June on Vermont's lower rivers and a week later on colder mountain drainages. The White River and Battenkill both produce memorable Green Drake evenings when large brown trout that spend the day invisible suddenly appear in flat water after 7pm. Bring a headlamp — the Coffin Fly spinner fall after dark is often the best fishing of the entire year.
Recommended: #8–10 Green Drake Wulff, Coffin Fly spinner
Ephemerella dorothea
Vermont's most reliable summer hatch and a staple on the Battenkill from June through August. Sulphurs hatch in the evening, typically beginning around 7pm and intensifying as the light fades. On the Battenkill, this is the prime summer hatch — trout rise consistently in the glides and flats throughout July. The emerger fished just under the surface film is often more productive than the dun during the height of the hatch. A #16–18 Sulphur Sparkle Dun or Parachute is the standard choice; carry Comparaduns for flat-water fish inspecting the fly closely.
Recommended: #16–18 Sulphur Comparadun, Sparkle Dun emerger
Isonychia bicolor
One of the most productive hatches of the Vermont fall season and a September staple on larger freestone rivers. Isonychia — also called Slate Drakes — are large (#10–12), fast-swimming nymphs that trout pursue aggressively before and during the dun emergence. The hatch fires in late afternoon and continues into evening on the White River, Winooski, and West River. September Isonychia action can rival anything June offered. Swing a soft hackle or wet fly down and across for the emerging nymph — a downstream drift is one of the rare times it consistently outfishes an upstream presentation.
Recommended: #10–12 Isonychia Comparadun, Soft Hackle Wet Fly
Baetis sp.
Vermont's most reliable all-season hatch — present spring and fall on every stream type and most consistent on overcast, drizzly days when other hatches won't fire. Spring BWOs peak in April and run through early May on all Vermont streams. The fall window is September through November and is especially strong on the Battenkill, where cold, raw October afternoons bring dense hatches over selective wild browns. When the weather turns ugly and other anglers head for the car, tie on a #18–22 Sparkle Dun or RS2 emerger and look for risers in flat water — you'll often have the pool to yourself.
Recommended: #18–22 Sparkle Dun, RS2 emerger
Vermont's trout season opens with Quill Gordon and Hendrickson hatches in late April and May — the most celebrated dry fly events in New England. The Hendrickson hatch on the Battenkill draws anglers from across the country, and it's well deserved. Blue-Winged Olives fish well throughout spring and fall on all Vermont stream types, particularly on overcast days when nothing else is happening.
June is Vermont's peak hatch month. The Green Drake (Ephemera guttulata) hatch fires at dusk on the White River, Battenkill, and major valley drainages — a brief but spectacular event with large browns rising freely after 7pm. Sulphur hatches provide reliable evening action from June through August on the Battenkill and other spring-influenced rivers, while Light Cahills cover most other Vermont streams through June and July.
Fall is exceptional in Vermont. Isonychia hatches in September on the White River and Winooski produce some of the year's best dry fly fishing, and Autumn Caddis combined with BWOs extend quality surface action through October against a backdrop of world-class fall foliage. Use FlyFishFinder's flow alerts to know when your target Vermont stream is at prime level and in fishable condition.
See Live Vermont River Conditions →Common Questions
The Hendrickson is Vermont's signature spring hatch and the most anticipated event on the Battenkill each year. It typically fires from late April through mid-May, peaking in early May when water temps reach the low 50s°F. The hatch is heaviest on overcast afternoons between 1–3pm. The Battenkill's clear, selective browns make precise presentation essential — a #12–14 Hendrickson Comparadun fished drag-free over rising fish is the classic approach.
June is Vermont's premier dry fly month. Carry #8–10 Green Drake Wulffs and Coffin Fly spinners for evening rises, #16–18 Sulphur Comparaduns and Sparkle Duns for late afternoon, and #12–14 Light Cahill Comparaduns as an all-around evening option. On the Battenkill, a #22–26 Trico Spinner may begin producing in the mornings by late June. Keep a few #18–22 BWO Sparkle Duns for any overcast afternoon.
The Battenkill fishes best from late April through June for dry fly action, with the Hendrickson (May) and Green Drake (early June) being the peak events. The Trico spinner fall from July through September provides demanding but rewarding morning fishing. September and October offer consistent BWO hatches and good dry fly action as temperatures drop. The Battenkill's wild brown trout are famously selective — arrive early and wade quietly.
Green Mountains freestone streams (Mad River, Dog River, Nulhegan) run cold and high in May, pushing major hatches like Hendrickson and Green Drake 1–2 weeks later than lower-elevation valley rivers. The Battenkill and West River, being spring-influenced and at lower elevations, can see Hendricksons as early as late April. Expect Quill Gordons and Hendricksons to arrive noticeably earlier on the Battenkill compared to higher-elevation streams in the Green Mountains.
The White River is Vermont's largest freestone system, holding brown trout, rainbow trout, and brook trout throughout its many branches. Focus on Hendrickson Comparaduns in May, Green Drake Wulffs in early June, and Light Cahill in June and July. The White River has an excellent Isonychia hatch in September — swing a #10–12 soft hackle or Isonychia Comparadun through the runs. Streamers produce throughout the season, especially during high water in spring.
May is Vermont's most celebrated hatch month — Hendricksons and March Browns overlap on most major rivers. June is the peak month for variety: Green Drake, Sulphur, and Light Cahill all overlap, producing evening rises across the state. September is outstanding for Isonychia and Autumn Caddis with fall foliage as a backdrop. April and October offer consistent BWO fishing on overcast days on every Vermont trout stream.
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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