Au Sable River
Grayling · Holy Waters
N Lower Michigan, USA
Open live forecast →Target species: Brown, Brook, and Rainbow.
Stream gauge: 04136000. Flow and water temperature update on every refresh.
Weekly AI Outlook as of 06/05/26
At 944 cfs, the Holy Waters is running higher than typical spring levels but still fishable with wading adjusted for the push. Water temp at 64°F has crossed the key threshold for Hex emergence — this is prime time for Michigan's most legendary hatch. Evening sessions from 7pm onward should produce the spinner falls that make this stretch famous. Focus on the deeper runs and undercuts where browns stage during daylight hours.
- Flow: 944 cfs — elevated but manageable, wade carefully and fish the slower inside bends where trout hold in higher water
- Hatches: Hex emergence zone at 64°F — evening spinners from 7-9pm, plus scattered Brown Drake activity in the deeper pools
- Water Temp: 64°F — perfect for Giant Mayfly activity, warm enough to trigger consistent evening emergence patterns
- Best Window: 7pm-dark for surface action, midday nymphing in the deeper Holy Waters runs between Burton's Landing and Wakeley Bridge
Generated weekly from live USGS gauge readings, weather forecasts, and recent fly shop reports. Updates Friday mornings.
About this Water
- Freestone
- Best months: Apr–Oct, peak June (Hex)
The Au Sable River through northern Michigan is the cradle of Michigan trout fishing and the site of America's first trout-only regulations. The Holy Waters — the catch-and-release flies-only stretch through Grayling — produces brown trout, brook trout, and the legendary Hex hatch through late June nights. The river's pace is slow, the gradient gentle, and the float-by-Au-Sable-river-boat tradition runs deep. The Mainstream below Burton's Landing offers some of the most photographed dry-fly water in the Midwest.
The Au Sable's Hex hatch — Hexagenia limbata, the largest mayfly in North America — emerges in late June through early July nights, producing some of the most exciting dry-fly fishing in the Midwest as enormous brown trout feed on inch-long mayflies in total darkness.
January Outlook
January in the Holy Waters section of the Au Sable. The spring-fed river stays open in Michigan winter. Walk-in midge fishing in the most revered stretch of Midwest trout water.
Productive Patterns
- Zebra Midge
- RS2
- Baetis Nymph
- Soft Hackle Midge
Tips
The Holy Waters (Burton's Landing to Wakeley Bridge) is walk-in only — no motors, no canoes in winter. The spring-fed water stays 46–52°F even in January cold. A peaceful, sacred experience in Michigan fly fishing's most hallowed stretch.
Water Notes
Spring-fed 400–650 cfs. Water 46–52°F year-round. No vehicle access in sections. Walk-in only. Quiet Michigan winter.
February Outlook
February fishing in the Holy Waters. The spring-fed section is at its most solitary and peaceful. Midge nymphs in the classic pools.
Productive Patterns
- Zebra Midge
- RS2
- Midge Pupa
- Soft Hackle
Tips
February is the quietest month in the Holy Waters. The spring seeps keep the river open. This is pilgrim fishing — a quiet contemplative visit to Michigan's most historically significant trout water.
Water Notes
Spring-fed 400–650 cfs. Water 46–52°F. Deep Michigan winter. Snowshoeing may be needed for access in some years.
March Outlook
March on the Holy Waters. Early Baetis activity begins as spring approaches. The section from Burton's Landing through the core of the Holy Waters begins seeing its first rises.
Productive Patterns
- Baetis Sparkle Dun
- Midge Dry
- RS2
- Elk Hair Caddis (small)
Tips
March is the transition month in the Holy Waters. The first Baetis activity of the year produces sporadic rises from fish that have been nymphing all winter. Walk-in access required.
Water Notes
Spring-fed 400–700 cfs. Water 48–54°F. Early spring transitioning. First rising fish of the year.
April Outlook
April spring fishing in the Holy Waters section. Early Hendrickson activity begins by mid-month. The iconic Au Sable spring season is starting.
Productive Patterns
- Quill Gordon
- Baetis Dun
- Hendrickson Nymph
- Soft Hackle Emerger
Tips
April is when the Holy Waters begins showing its summer character. Quill Gordon and early Hendrickson activity. No motors or canoes — the walk-in experience is peaceful. Fish the early evening window.
Water Notes
Spring-fed 400–700 cfs. Water 48–54°F. Spring hatches beginning. The Holy Waters walk-in experience is excellent.
May Outlook
May Hendrickson season in the Holy Waters. The most famous section of the Au Sable is fishing at its spring best. Hendrickson, Sulphur, and Caddis produce consistent evening action.
Productive Patterns
- Hendrickson Dry
- Sulphur Sparkle Dun
- Elk Hair Caddis
- Soft Hackle
Tips
The Holy Waters in May is Michigan fly fishing at its purest. Walk in at Burton's Landing or Wakeley Bridge. Fish the evening hatch windows. The large brown trout are concentrated in the deep bends.
Water Notes
Spring-fed 400–700 cfs. Water 50–56°F. Prime spring conditions on the Holy Waters.
June Outlook
The Holy Waters section of the Au Sable between Burton's Landing and Wakeley Bridge is the epicenter of the famous summer hatches. Brown Drake and the beginning of Hex.
Productive Patterns
- Brown Drake #10
- Sulphur
- Hex Dry #6
- Elk Hair Caddis
Tips
The Holy Waters is walk-in or canoe access only — no motors. The most revered trout water in the Midwest. Fish the evening hatches from 7pm onward.
Water Notes
400–700 cfs. Water 52–58°F. Spring-fed and consistent. The Holy Waters is the most managed and protected stretch of the river.
July Outlook
The Hexagenia hatch is the reason many anglers visit the Holy Waters. One of the most remarkable natural events in Midwest fly fishing.
Productive Patterns
- Hex Dry #6
- Hex Spinner
- Brown Drake Spinner
- Extended Body Hex
Tips
Fish the Hex hatch by night with a floating line. Listen for the 'slurping' rises in the darkness. The fish key on the spinners after the hatch. This is night fishing — bring a headlamp and know the river well.
Water Notes
400–700 cfs. Water 54–60°F. Night fishing required for the Hex hatch. Be prepared for cold nights even in July.
August Outlook
August post-Hex season on the Holy Waters. Trico spinner falls at dawn and evening Caddis produce fish on the surface. The pressure drops from the Hex crowds.
Productive Patterns
- Trico Spinner
- Elk Hair Caddis
- Hopper
- Parachute Ant
Tips
August on the Holy Waters is excellent after the Hex crowds depart. Trico spinner falls begin at first light and can produce large fish. The evening caddis continues. Walk-in access from Burton's Landing for the quietest experience.
Water Notes
350–650 cfs. Water 52–58°F. Good post-Hex conditions. Summer low water.
September Outlook
Fall fishing on the Holy Waters with BWO and Caddis hatches. The spring-fed section maintains excellent water quality through fall.
Productive Patterns
- Blue Winged Olive
- Elk Hair Caddis
- Mahogany Dun
- Streamer
Tips
September on the Holy Waters is excellent with reduced pressure. BWO hatches on overcast afternoons. The large brown trout begin pre-spawn behavior. One of the Midwest's finest fall trout experiences.
Water Notes
350–650 cfs. Water 50–56°F. Excellent fall conditions on the spring-fed Holy Waters.
October Outlook
Brown trout spawning season on the Holy Waters. The largest fish of the year are moving and aggressive. Streamer fishing and egg patterns produce.
Productive Patterns
- Streamer
- Egg Pattern
- BWO Dry
- Soft Hackle
Tips
October in the Holy Waters is spectacular — the biggest browns are active and visible in the gravel sections. The walk-in experience is at its most atmospheric in fall color. Respecting redds is important.
Water Notes
400–700 cfs. Water 48–54°F. Brown trout spawning season. Handle all fish gently.
November Outlook
November post-spawn fishing in the Holy Waters. Brown trout are recovering from the spawn and feeding aggressively. The river is quiet and beautiful.
Productive Patterns
- Streamer
- Soft Hackle
- Midge Nymph
- Elk Hair Caddis (small)
Tips
November in the Holy Waters is an excellent low-pressure fishing opportunity. Post-spawn browns feed aggressively. The walk-in access is peaceful in late fall. Last good month before the deep winter quiet.
Water Notes
400–700 cfs. Water 46–52°F. Post-spawn conditions. The spring-fed river remains consistent.
December Outlook
December in the Holy Waters. The spring-fed river is open while Michigan is in winter. Midge nymphing in the legendary stretch of Au Sable water.
Productive Patterns
- Zebra Midge
- RS2
- Baetis Nymph
- Soft Hackle Midge
Tips
December fishing in the Holy Waters is a Michigan winter rite. The spring seeps keep the most famous sections open. Walk in from Burton's Landing or Wakeley Bridge. A quiet, meditative experience in a legendary place.
Water Notes
Spring-fed 400–650 cfs. Water 46–52°F. December on the iconic Holy Waters — open and fishable.
Hatch Calendar
| Insect | Peak | Active | Size | Productive Patterns |
|---|---|---|---|---|
| Hex (Giant Mayfly) Hexagenia limbata |
Jun | Jun, Jul | #4–6 |
|
| Hendrickson Ephemerella subvaria |
Apr, May | Apr, May | #12–14 |
|
Access & Approach
Grayling, MI is the primary base. Public access at Burton's Landing, Stephan Bridge, and downstream. Michigan fishing license + trout stamp required. Holy Waters catch-and-release / flies-only regulations.
Nearby Fly Shops
- Old Au Sable Fly Shop
- Gates Au Sable Lodge
- Mangled Fly
- The Northern Angler
- Hawkins Outfitters
Regulations & License
Fishing in Michigan requires a current license. Always verify season dates, bag limits, and any special-regulation waters before you fish.
Michigan fishing regulations & license →
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About Current
Au Sable River conditions on Current combine real-time flow data (USGS, WSC, CDEC, CEHQ), weather, tide predictions, hatch probabilities calibrated to this specific water, and recent fly shop reports from the area.
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