Chinook and coho prime for Chicago's Lake Michigan May run

What's Biting

What's Next

The offshore salmon program on Lake Michigan's Illinois waters is entering one of its most reliable windows of the year. Mid-May typically coincides with peak spring salmon activity as upper-column temperatures warm toward the mid-to-upper 40s°F, pushing fish into defined depth bands that reward disciplined vertical presentation.

Based on the pattern emerging on the Michigan shoreline — where forum contributors on the Michigan Sportsman Forum reported productive king action during the first days of May in 40-50 feet of water — Chicago-area trollers working the same depth range have a logical starting point. Those reports noted that divers and riggers fished close to bottom consistently outperformed higher presentations. This reflects a common early-season thermal stratification: as surface temperatures warm faster than deeper water, salmon concentrate near the thermocline. Expect that stratification to deepen gradually through the week as May warmth builds, which may push the productive zone slightly deeper — 50-70 feet down — by the weekend.

The waning crescent moon phase means darker nights through mid-week, which historically compresses salmon feeding into low-light windows. Plan to be on the water before first light and fish hard through the first two hours after sunrise. Coho tend to run shallower than kings during these transitions and can be intercepted in the 20-35 foot range on mid-column presentations as conditions allow.

Illinois-Indiana Sea Grant's three nearshore Lake Michigan buoys are being re-deployed this spring per their recent update. Once those instruments come online, real-time water temperature and wave-height data will sharpen depth decisions considerably — check for buoy readings before heading out. Cold-water upwelling events driven by sustained northeast winds are a common May variable on Chicago's lakefront; they can push fish shallower and closer to the piers almost overnight. Calm, warming windows tend to push fish deeper and farther offshore.

Check current Illinois DNR regulations before launching, as salmon bag limits and size rules apply and may vary by species.

Context

Mid-May is historically the heart of the spring salmon season on Lake Michigan near Chicago. The annual Chinook and coho run builds through April as alewife schools move into warming nearshore water, drawing predators up from winter depths. By the second week of May, fish are typically concentrated in the 30-70 foot range — consistent with the depths described on the Michigan side this year.

The WI DNR Lake Michigan Fishing Report provides important stock-level context for the 2026 season. Last year's lake-wide harvest was exceptional: more than 210,000 coho were taken — a new record — and Chinook totaled over 160,000, the highest king count since 2012. The WI DNR attributes both marks to strong recent alewife year-classes that improved survival of stocked smolts. That well-fed cohort has now aged into legal-size fish, which underpins optimism for this spring across all Lake Michigan ports, including Chicago.

On the management side, the WI DNR has been holding public meetings on proposed new total allowable catch levels for Lake Michigan and Green Bay lake whitefish, reflecting the kind of active regulatory attention that sustains the broader fishery over the long term. Those proceedings center more on commercial and tribal whitefish harvest than recreational salmon trolling, but they signal the careful management framework that keeps the lake productive season after season.

Illinois-Indiana Sea Grant operates three nearshore Lake Michigan buoys, redeployed each spring to support public safety and angler planning. Their deployment timing aligns squarely with the spring salmon season. No comparative buoy readings are available for this specific report window, but historically mid-May on Chicago's lakefront sees water temperatures in the 44-52°F range — squarely in the zone where salmon hold and feed aggressively ahead of the summer warm-up.