Hendrickson
Ephemerella subvaria
Mayfly
- Peak week
- May 15 – Jun 5
- Intensity
- Heavy
- Time of day
- Afternoon
- Water temp
- 50–58°F · peak 55°F
Top flies
Hendrickson Parachute #12-14 · Red Quill Spinner #12-14 · Pheasant Tail Nymph #14
Hatch calendar
Lamoille River hatch calendar.
- Freestone
- Mixed
- brown trout
- brook trout
- rainbow trout
Northern Vermont freestone with mixed wild and stocked trout. Shorter season but strong hatches in May and June.
Verify with the agency before fishing
Fishing regulations change every season. This page is a summary maintained by Bield — bag limits, exact dates, and species-specific rules must be verified with Catamount Fishing Adventures before each trip.
What's hatching now
May on the water.
Midge
Chironomidae spp.
Midge- Peak week
- Year-round
- Intensity
- Moderate
- Time of day
- Midday
- Water temp
- 32–60°F · peak 40°F
Top flies
Griffith's Gnat #20-24 · Zebra Midge #20-22 · WD-40 #20
Blue Winged Olive
Baetis spp.
Mayfly- Peak week
- Apr 25 – May 25
- Intensity
- Moderate
- Time of day
- Afternoon
- Water temp
- 45–55°F · peak 50°F
Top flies
Parachute BWO #18-20 · CDC Comparadun #18-20 · Pheasant Tail Nymph #18
Spring emergence
March Brown
Maccaffertium vicarium
Mayfly- Peak week
- May 25 – Jun 20
- Intensity
- Moderate
- Time of day
- Afternoon
- Water temp
- 55–65°F · peak 60°F
Top flies
March Brown Parachute #10-12 · Grey Fox Comparadun #12 · March Brown Nymph #12
Full year calendar
Twelve months on Lamoille River.
Each row is a hatch species. Bar color = type, opacity = intensity, peak month outlined. The current month is highlighted on the timeline.
MayflyCaddisStoneflyMidgeTerrestrial· peak month outlined · intensity = bar opacity · current month highlighted
Hatch species on Lamoille River
The bug calendar in detail.
Midge
Chironomidae spp.
MidgeMiddayWater-temperature trigger
30°F32–60°Fpeak 40°F80°F- Duration
- 52 weeks
- Also called
- Chironomids · Snowflies
Top fly patterns
- Griffith's Gnat #20-24
- Zebra Midge #20-22
- WD-40 #20
- Disco Midge #22
Year-round food source — the only consistent option on tailwaters in winter. On cold sunny days look for noses sipping clusters in slow water.
Blue Winged Olive
Baetis spp.
MayflyAfternoonWater-temperature trigger
30°F45–55°Fpeak 50°F80°F- Duration
- 6 weeks
- Also called
- BWO · Olive
Top fly patterns
- Parachute BWO #18-20
- CDC Comparadun #18-20
- Pheasant Tail Nymph #18
- RS2 #20
Most reliable Eastern hatch. Two emergences — spring (March-April) and fall (September-October). Best on overcast, drizzly days.
Hendrickson
Ephemerella subvaria
MayflyAfternoonWater-temperature trigger
30°F50–58°Fpeak 55°F80°F- Duration
- 3 weeks
- Also called
- Red Quill · Dark Hendrickson
Top fly patterns
- Hendrickson Parachute #12-14
- Red Quill Spinner #12-14
- Pheasant Tail Nymph #14
- Hendrickson Comparadun #14
First substantial mayfly hatch on most Eastern rivers. Spinner falls in evening can be as productive as the dun emergence.
March Brown
Maccaffertium vicarium
MayflyAfternoonWater-temperature trigger
30°F55–65°Fpeak 60°F80°F- Duration
- 4 weeks
- Also called
- Grey Fox · American March Brown
Top fly patterns
- March Brown Parachute #10-12
- Grey Fox Comparadun #12
- March Brown Nymph #12
Sporadic emergence rather than a heavy hatch — but trout key on individual large duns drifting through. Freestone-river specialty.
Sulphur
Ephemerella dorothea / invaria
MayflyEveningWater-temperature trigger
30°F55–68°Fpeak 62°F80°F- Duration
- 6 weeks
- Also called
- Pale Watery · Little Yellow May
Top fly patterns
- Sulphur Parachute #16-18
- Sulphur Comparadun #16-18
- Sulphur Sparkle Dun #16
- Pheasant Tail Nymph #16
- Sulphur Spinner #18
The most important mayfly hatch on Eastern rivers. Reliable emergence + spinner fall every evening for 4-6 weeks. Match the spinners with rusty-bodied patterns.
Light Cahill
Stenacron / Leucrocuta spp.
MayflyEveningWater-temperature trigger
30°F60–72°Fpeak 65°F80°F- Duration
- 5 weeks
- Also called
- Cahill
Top fly patterns
- Light Cahill Parachute #14-16
- Cahill Comparadun #14
- Light Cahill Spinner #14
Pale yellow-cream mayfly. Less intense hatch than Sulphur but reliable across many Eastern rivers in late spring through early summer.
Tan Caddis
Hydropsyche spp.
CaddisEveningWater-temperature trigger
30°F58–72°Fpeak 64°F80°F- Duration
- 10 weeks
- Also called
- Spotted Sedge · Cinnamon Caddis
Top fly patterns
- Elk Hair Caddis #14-16
- X-Caddis #14
- LaFontaine Sparkle Pupa #14
- Tan Caddis Soft Hackle #14
Workhorse summer caddis. Heavy emergences and egg-laying flights at dusk through summer. Drop a soft hackle on the swing during the evening.
Slate Drake
Isonychia bicolor
MayflyEveningWater-temperature trigger
30°F55–70°Fpeak 62°F80°F- Duration
- 12 weeks
- Also called
- Iso · Mahogany Dun (spinner)
Top fly patterns
- Slate Drake Parachute #12
- Iso Comparadun #12
- Mahogany Spinner #12
- Iso Nymph #12 (swimming nymph)
Long-running hatch from June into October. Nymphs are strong swimmers and crawl out of the water to emerge — fish a swung wet fly through riffles.
Terrestrials
(beetles, ants, hoppers)
TerrestrialAfternoonWater-temperature trigger
30°F60–78°Fpeak 70°F80°F- Duration
- 12 weeks
- Also called
- Hoppers · Ants
Top fly patterns
- Foam Hopper #10-12
- Foam Beetle #14-16
- Para-Ant #16-18
- Chernobyl Ant #10
Not a hatch but the most important summer trout food in many Eastern systems. Fish tight to grassy banks and overhanging trees. Hopper-dropper rigs are deadly July through September.
River info
- River type
- Freestone
- Primary species
- brown_trout · brook_trout · rainbow_trout · wild · stocked
- Management
- Mixed
- Counties
- Lamoille County
- Elevation
- 650 ft
- Access
- Public access along Vermont Route 15 corridor and adjacent state forests.
Live water temperature & hatch alerts.
Bield Fish reads USGS gauges, watches for the trigger window, and pings you when Lamoille River hits the temperature for your target hatch.
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