Free Resource · Updated 2026
The complete fly hatch chart for Massachusetts tailwater fisheries, Berkshire freestone rivers, and wild brook trout streams. From the Deerfield River's reliable Sulphur and Isonychia hatches to the Swift River, Westfield, Millers, Ware, and Nissitissit. Select your stream below for peak hatch timing, fly pattern recommendations, and current month highlights for 2026.
Massachusetts Hatch Calendar
Massachusetts Streams
Deerfield River · Swift River (MA)
The Deerfield River below Fife Brook Dam in Charlemont and the Swift River below Quabbin Reservoir in Ware are Massachusetts's most consistent trout fisheries. Cold dam releases suppress summer water temps and extend the hatch season at both ends of the year. The Deerfield is the more diverse system, with Green Drake and Isonychia hatches that rival any New England river. The Swift River runs cold and clear year-round — a technical tailwater with selective fish and reliable Sulphur and Trico hatches through the summer months.
Westfield River · Millers River
High-gradient freestone rivers draining the Berkshire hills and western Pioneer Valley. Hatch timing is slightly earlier than New Hampshire's White Mountains but comparable to southern New England generally. These streams hold wild brown and brook trout in the upper reaches and support productive hatches from April through October. The Westfield is the more diverse fishery, with Green Drake and Isonychia hatches. The Millers offers accessible public water and reliable Hendrickson action in May on a stream that rarely sees much pressure.
Ware River · Nissitissit River
Lower-gradient streams in central and eastern Massachusetts with earlier hatch timing compared to Berkshire rivers. The Ware River holds brown and brook trout with consistent Sulphur and Light Cahill hatches in summer. The Nissitissit near Pepperell is one of the state's best native brook trout streams — smaller and more technical, with hatches starting in late April and running through October. Both rivers fish well on overcast days in spring and fall when BWO activity is consistent.
The Why Behind the Chart
Epeorus pleuralis
Massachusetts's first significant dry fly hatch and a signal that the season has opened in earnest. Quill Gordons fire in the afternoon when water temps climb into the mid-to-upper 40s°F — typically between 2–4pm on warm, sunny April days. On lower-elevation streams like the Nissitissit and Ware River the hatch may begin as early as mid-April. On Berkshire freestone rivers and colder tailwaters it usually waits until late April or early May. Trout that haven't seen a dry fly in months respond aggressively to this first big hatch of the year.
Recommended: #12–14 Quill Gordon Dry, Hare's Ear Nymph
Ephemerella subvaria
The Hendrickson is Massachusetts's most widely distributed and reliable spring hatch — present on every quality trout stream in the state. It fires in the early-to-mid afternoon on overcast days when water temps are in the low-to-mid 50s°F. On lower-elevation rivers the hatch may begin in late April; on Berkshire streams and the Deerfield tailwater it typically peaks the first two weeks of May. Fish the dun in the film with a downstream-and-across drift through flat water and slow runs. One of the most productive hatches of the year for consistently rising fish.
Recommended: #12–14 Hendrickson Comparadun, A.P. Nymph
Ephemera guttulata
The most anticipated hatch on Massachusetts freestone rivers and the highlight of the dry fly calendar. Green Drakes fire at dusk when water temps reach 55–62°F — on the Deerfield and Westfield this typically means mid-June. Large brown trout that hold in deep runs all day come to the surface after 7pm during this hatch. The Deerfield River's Charlemont section is one of the most reliable Green Drake venues in New England. Bring a headlamp — the spinner fall after dark can be the best fishing of the night.
Recommended: #8–10 Green Drake Wulff, Coffin Fly spinner
Ephemerella dorothea
A consistent evening hatch that runs through the heart of summer on Massachusetts's tailwaters and lower-gradient rivers. Sulphurs begin in June and remain productive into August on the Swift River and Deerfield, where cold dam releases keep water temps in range long after freestone streams warm. The hatch fires in the evening, typically from 7pm to dark, and produces steady rises from fish that can be selective about size and color. A #16–18 Sulphur Comparadun or Sparkle Dun is standard; carry both the light and dark versions.
Recommended: #16–18 Sulphur Comparadun, Sparkle Dun
Isonychia bicolor
One of the most underrated hatches in New England and a September highlight on Massachusetts's larger freestone rivers. Isonychia (also called Slate Drakes) are large (#10–12), fast-swimming nymphs that trout pursue aggressively before the dun emerges. The hatch fires late afternoon and runs into evening. On the Deerfield and Westfield, September Isonychia action can rival anything the summer offered. Swing a soft hackle or wet fly down and across to imitate the emerging nymph — one of the few situations where a downstream swing consistently outfishes a dry fly upstream presentation.
Recommended: #10–12 Isonychia Comparadun, Soft Hackle Wet Fly
Baetis sp.
Massachusetts's most dependable all-season hatch — present spring and fall on every stream type and most reliable on overcast, drizzly days. Spring BWOs peak in April; the fall window runs September through November. On the Swift River and Deerfield tailwater, fall BWOs can fire on cold October afternoons that push most anglers off the water. When the weather turns ugly and the thermometer drops, tie on a #18–22 Sparkle Dun or RS2 and look for rising fish in flat water. You'll often have the river to yourself in October.
Recommended: #18–22 Sparkle Dun, RS2 emerger
Massachusetts's trout season opens with Quill Gordon and Hendrickson hatches in April and May. Classic New England dry fly fishing on freestone streams running cold from snowmelt. Blue-Winged Olives fish well throughout spring and fall on all stream types and are especially productive on overcast days when nothing else is cooperating.
June brings the best hatches of the year. The Green Drake (Ephemera guttulata) fires at dusk on the Deerfield and Westfield rivers, a brief but spectacular event that draws anglers from across southern New England. Sulphur and Light Cahill hatches provide reliable evening action through June and July, particularly on the Swift River and Deerfield where cold tailwater keeps fish active through the summer.
Fall is underrated in Massachusetts. Isonychia hatches on the Deerfield and Westfield in September produce some of the year's best dry fly fishing, and Autumn Caddis combined with BWOs extend quality surface action through October. Use FlyFishFinder's flow alerts to know when your target Massachusetts stream is at prime level and dropping into fishable range.
See Live Massachusetts River Conditions →Common Questions
The Hendrickson typically fires in Massachusetts from late April through the first two weeks of May. On lower-elevation rivers like the Ware River and Nissitissit it may begin as early as mid-April. On the Deerfield and Westfield in the Berkshires it usually peaks the first week of May. The hatch fires mid-afternoon on overcast days when water temps are in the low-to-mid 50s°F — one of the most reliable and widely distributed hatches in the state.
May is the Hendrickson month across virtually every Massachusetts trout stream. Carry #12–14 Hendrickson Comparaduns and A.P. Nymphs as your go-to. Add a #10–12 March Brown for larger rivers like the Deerfield and Westfield where the hatch overlaps in late May. BWO Sparkle Duns in #18–20 cover the overcast days between hatches. A Pheasant Tail or Hare's Ear nymph fished in the film will produce between hatches on most streams.
The Deerfield River below Fife Brook Dam in Charlemont fishes well nearly year-round thanks to cold tailwater releases, but the peak season for dry fly fishing is May through October. The Hendrickson and March Brown in May, Green Drake in June, Sulphur and Light Cahill in June–July, and Isonychia in September are the highlights. Fall BWOs extend quality surface action through October. Check Fife Brook Dam release schedules — flow fluctuations affect wading safety and fishing quality.
Massachusetts tailwaters like the Deerfield and Swift River run cooler than freestone streams in summer, which pushes some hatches later and extends the season. Sulphurs and Tricos that would fade on warm freestone streams in July and August remain productive on the Swift River's cold Quabbin outflow. Spring hatches like Quill Gordon and Hendrickson are relatively similar in timing, but tailwater insects tend to hatch more predictably day to day. Freestone streams like the Westfield and Millers are more vulnerable to summer low flows and warm water.
The Swift River below Quabbin Reservoir in Ware is a technical tailwater with clear, cold water and selective fish. Small fly sizes and light tippet are standard. Focus on #18–22 BWO Sparkle Duns and RS2 emergers in spring and fall, #16–18 Sulphur Comparaduns in June and July, #22–26 Trico spinners in August mornings, and #20–22 midges in winter. Longer leaders and 6x–7x tippet are typical on this water.
May is Massachusetts's peak hatch month, with Hendricksons and March Browns on most streams. June brings the Green Drake on the Deerfield and Westfield and evening Sulphur hatches on tailwaters. September is the best fall month — Isonychia on the Deerfield and Westfield produces some of the year's best dry fly fishing, and Autumn Caddis extends quality surface action through October. The Deerfield and Swift River fish well year-round thanks to cold tailwater temperatures.
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