Great Lakes
Au Sable River
Live Conditions
Au Sable River — Au Sable River near Red Oak, MI
7-Day Flow
↓ Falling
24-Hr Pressure
28.83 inHg · → High/stable
Local Weather
Tough conditions — fish deep
Today
🌧️Rain
80° / 67°
0.16"
Tomorrow
🌫️Foggy
88° / 65°
Wed
🌧️Rain
83° / 65°
0.07"
Thu
🌦️Drizzle
85° / 61°
0.01"
Weather by Open-Meteo · No API key · Updated every 30 min
What should I fish today?
⚡ AIAI-powered recommendation using today's live flow, temperature, and hatch data.
9.4
Time of Day
Using: 911 CFS · 60.6°F · ISONYCHIA
What should I pack?
Rod, flies, tippet, and safety gear specific to today's Au Sable River conditions.
🪰 Hatch Calendar
Au Sable River · September · Early Fall
🟢 Active now at 60.6°F water
🟡 Approaching — within 5°F of trigger range
Select month
ISONYCHIA (Mahogany Dun, size 12-14) afternoons — fall fishing's big-fly hatch. BWOs (size 18-20) on overcast days. Cool nights; brown trout active and aggressive. Often the best month for large fish.
🟢 Active · 🟡 Approaching · ⚪ Seasonal only
River Map
About Au Sable River
The Au Sable River is one of the most iconic trout streams in the United States — the eastern equivalent of the Madison. The 'Holy Water' section from Grayling downstream through the Grayling State Forest is a no-kill, artificials-only stretch that produces wild brown trout of legendary size. The Hex hatch in late June and early July draws anglers from across the country for marathon nights of rising fish. Arctic grayling were native to the Au Sable until their extinction around 1936 — Michigan DNR has been studying reintroduction as of 2026.
Regulations
Multiple Type 1 (Gear Restricted) and no-kill artificials-only sections throughout. Holy Water section (Grayling to Burton Landing): no-kill, artificial lures and flies only. Verify exact section boundaries in the current Michigan DNR Inland Trout & Salmon Regulation Guide — boundaries are marked by signs and updated annually. Michigan Fishing License required ($27 resident / $77 non-resident). Season opens last Saturday of April (2026 opener: April 25).
Learn More
Guides to help you fish Au Sable River with more confidence.
Michigan Fly Fishing Regulations Guide
Michigan fishing license, the last-Saturday-in-April trout opener, Type 1/Type 2 Gear Restricted designations, the no-kill artificials-only Au Sable…
Trout Species of Michigan
Michigan's native Brook Trout (the state fish, dominant in UP rivers and cold headwaters), the introduced Brown Trout (first stocked in the U.S. in…
The Hex Hatch: Michigan's Greatest Night on the Water
The Hexagenia limbata hatch on the Au Sable Holy Water is the one event that brings the largest brown trout in Michigan rivers to the surface after…