Fall turnover: what it is and how to fish it

Why lakes "flip" in the fall, how to tell when it's happening, and where to find fish before, during and after turnover.

By the FreeFish team · 3 min read · Updated October 14, 2026

Every fall, many anglers hit a lake that was producing great fishing a week earlier and find murky water, strange smells and almost no bites. The usual culprit is fall turnover, a natural mixing of the lake that happens as the weather cools. It is temporary, it is predictable, and once you understand it you can work around it.

Why lakes turn over

In summer, deeper lakes form layers. Sun-warmed water floats on top, and colder, denser water sits on the bottom. The narrow transition between them is the thermocline. Because the layers barely mix all summer, the bottom layer often runs low on oxygen as plant material decays, and fish live mostly in the upper layer.

In fall, cool nights and wind chill the surface. That water gets denser and sinks. Eventually the surface cools to roughly the same temperature as the bottom, the layers stop resisting each other, and wind mixes the whole lake top to bottom. That mixing is turnover.

How to tell it's happening

• Murky or "dirty" water on a lake that is normally clearer, sometimes with bits of floating debris.
• A sulfur or rotten-egg smell as low-oxygen bottom water reaches the surface.
• Foam or scum lines on the surface.
• Similar water temperatures at the surface and in deeper water if you have a thermometer or electronics.
• Fish scattered at all depths on sonar, rather than holding at one level.

Timing

Turnover usually happens in early to mid fall in northern states and later in the South, but it varies with weather and lake size. A few patterns are consistent:

• Shallow, small lakes turn first. They cool faster. Large, deep lakes turn later and can take longer to settle.
• Cold, windy weather speeds it up. A strong cold front with wind can trigger it quickly.
• It does not last forever. Most lakes are tough for roughly a week or two, then settle as the water clears and oxygen evens out.
• Very shallow lakes may not stratify at all in summer, so they never really "turn over."

How to fish during turnover

Fish do not disappear, but they become scattered and less predictable while conditions change around them. A few strategies help:

1. Fish a different lake. This is the most effective option. If your lake has turned, try one that is shallower (and may have already finished) or larger and deeper (and may not have started yet).
2. Go shallow. Shallow areas often settle first and may have the best oxygen and clarity. Look for flats and shorelines with healthy green weeds.
3. Look for living vegetation. Green weeds produce oxygen and hold baitfish. Dead, brown weed beds are less productive.
4. Find the bait. Predators will be near baitfish. Watch for birds working the surface and baitfish on your electronics.
5. Slow down and downsize. Lethargic fish often respond better to slower presentations and smaller baits.
6. Try rivers and creek mouths. Moving water is not affected the same way and can be a great fall alternative.

After turnover: some of the best fishing of the year

Once the lake settles, oxygen is spread evenly through the water column, water clears, and fish are free to use the whole lake. Many species feed heavily ahead of winter. Look for:

• Baitfish schools in creek arms, bays and on main-lake points.
• Steep breaks next to shallow feeding flats, which give fish easy access to both.
• Remaining green weed beds, which become magnets as other vegetation dies off.

Crankbaits, jerkbaits, swimbaits and jig-and-minnow combinations are all fall favorites. See our guides to fall walleye and bass through the year for species details.

A note on safety

Fall weather changes quickly, and the water is getting cold. Cold water can cause cold shock and exhaustion fast if you fall in, even on a mild day. Wear a life jacket, dress in layers, check the forecast for wind, and let someone know your plans.