The 2026 Hexagenia hatch will peak on Michigan’s Au Sable mainstream the last week of June through the first few days of July, with the Pere Marquette running roughly a week earlier and Wisconsin’s Bois Brule and Wolf finishing late June through mid-July. Fish the spinner fall at 10:00 to 10:30 p.m., not just the emergence — and on the Brule, plan around Wisconsin’s 30-minute-after-sunset fishing prohibition, which changes the whole trip.
This is a planning guide for Hex Week on the three rivers most worth a visiting angler’s drive: the Au Sable in northern Michigan, the Pere Marquette an hour and a half west, and the Bois Brule in far northern Wisconsin. Each fishes the same insect — North America’s largest mayfly, with a body and wingspan near two inches — but the experience on each is fundamentally different.
When the 2026 Hex hatch peaks on each river
The standard Au Sable mainstream window is roughly June 20 through July 15. Peak is the last week of June into the first few days of July, when water temperature reaches 66°F (Au Sable guide Matt Verlac’s published optimum). The Pere Marquette runs a week or two earlier — late June peak in the flies-only section from M-37 to Gleason’s Landing — and the lower river from Walhalla to Scottville extends Hex hatching later into July.
Wisconsin’s Bois Brule and Wolf River fire from late June through mid-July, with the spring-fed upper Brule running slightly later than warmer freestone water. Lake-population Hex hatches roughly 7–10 days earlier than river populations on the same latitude.
The hatch itself is one event per night. Duns emerge in the last hour of light. Spinners fall in mating swarms an hour or so later, at altitude, with the bulk falling between roughly 10:00 and 10:30 p.m. on Michigan’s rivers. Cold fronts, hard rain, sustained wind, and bright full-moon nights can collapse the spinner fall entirely.
How to fish the Hex hatch — gear, flies, and presentation
The published consensus on tackle is heavier than first-timers expect. Hawkins Outfitters recommends a 2X six-foot leader with no tippet attached — short, stout, and direct, because you cannot see, the water is full of logs, fish average large, and long fights in warm water kill released trout. Baldwin Bait & Tackle recommends stepping up to a 6- or 7-weight rod specifically for Hex, both to turn over wind-resistant size 4–6 deer-hair flies and to bully a brown out of timber.
The essential fly box: Roberts Yellow Drake (sizes 6–8 XL), Hex Spinner (4–8), Hex Comparadun or Parachute Hex Dun, Borchers Drake in larger sizes for the spinner phase, and Galloup’s Hex Wiggler for the swimming nymph just before duns hit the surface. Add Hex emergers and cripples for the back half of the week, when fish wise up to standard parachutes.
Three presentation rules from the guides: every cast is a reach cast, cast eight to ten feet above the fish and mend before the fly arrives, and wait on the set. Red-filter headlamps only — never white light during the spinner fall. Fight fish hard and land them fast. Anglers of the Au Sable‘s 70 Degree Pledge applies most directly to the back half of Hex week on the Mio-to-Alcona stretch.
Choosing the right river for a 2026 Hex trip
The Au Sable is the famous one and the most crowded. Its Holy Water — Burton’s Landing to Wakeley Bridge — is the epicenter; bigger browns concentrate from Wakeley through McMaster’s to Mio and on the Trophy Water below Mio Dam. The South Branch through the 4,493-acre Mason Tract is the quieter alternative. Grayling is the hub: Gates Au Sable Lodge, Old Au Sable Fly Shop, Hawkins Outfitters.
The Pere Marquette offers earlier timing in its flies-only catch-and-release section (M-37 to Gleason’s, 8 miles) and later, larger-water Hex on the lower river. Pere Marquette River Lodge in Baldwin is Orvis-endorsed; Baldwin Bait & Tackle is the local shop; Schmidt Outfitters in Wellston covers both the Manistee and the PM at a published $350 day rate.
The Bois Brule is the contrarian pick. Wisconsin DNR prohibits fishing from 30 minutes after sunset to 30 minutes before sunrise on the Brule — so the Michigan-style midnight Hex experience is not legal here. Wisconsin Hex happens at last light, in a canoe-and-wade tradition that goes back generations. Fly By Night Guide Service (Damian Wilmot) is the Brule’s signature operation; Tight Lines Fly Shop carries his Brule patterns.
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Bottom line
Plan two consecutive nights minimum, three if you can. Build in a buffer night for weather. Show up a week early to fish the Brown Drake and Isonychia at twilight if the long-range forecast looks rough. Verify current 2026 regulations on the Wisconsin DNR site for the Brule and the Michigan DNR digest for the Au Sable and Pere Marquette before booking.
FAQ
What is the Hexagenia hatch?
The Hexagenia hatch is the annual emergence of Hexagenia limbata, North America’s largest mayfly, with a body and wingspan near two inches. It happens once per year in the upper Midwest from roughly mid-June through mid-July. Adults emerge at sundown and the mating spinners fall to the water about an hour later, triggering aggressive surface feeding by the largest trout in the river.
When does the Hex hatch peak in 2026 on the Au Sable?
The Au Sable mainstream Hex hatch typically peaks the last week of June into the first few days of July, with the window running roughly June 20 through July 15. Peak conditions require water temperatures near 66°F, calm humid evenings, and an absence of cold fronts or bright moons. The Pere Marquette runs about a week earlier; the Bois Brule peaks late June through mid-July.
What flies do you use for the Hexagenia hatch?
Carry Roberts Yellow Drake in sizes 6–8 XL, Hex Spinners in 4–8, a Hex Comparadun or Parachute Hex Dun, Borchers Drake in larger sizes for the spinner phase, and Galloup’s Hex Wiggler nymph. Add emergers and cripples for late-week fish that have seen pressure. Tippet should be 2X to 3X — heavier than typical dry-fly fishing — because nights, logs, big fish, and warm water all argue against light leaders.
Can you fish at night during the Hex hatch in Wisconsin?
No — fishing on the Bois Brule is prohibited from 30 minutes after sunset to 30 minutes before sunrise under Wisconsin DNR rules. The famous Michigan-style “midnight Hex” experience is not legal on Wisconsin’s signature Hex river. Wisconsin Hex fishing happens at last light, not in full dark. Confirm current Wisconsin trout regulations before any trip; other Wisconsin trout water may have different night-fishing provisions.
How many nights do I need to plan for a Hex trip?
Plan two consecutive nights minimum; three is materially better. Hex has high night-to-night variance — a single cold front, full moon, or windy stretch can collapse the spinner fall. Boyne Outfitters‘ Ethan Winchester reports that out of three booked nights on the Au Sable, “it’s usually good bugs on two of those nights.” A one-night trip carries a real chance of zero.
