July is the start of king season in Ludington. The first part of the month the fish are scattered and as the water warms up the thermocline creates a layer that the kings lie below making them easier to catch. This underwater barrier traps alewives and other baitfish at the edge of the warm water above it. The kings prefer 41-46 degrees as their home and feed in warmer temps even into the upper 50s. August will throw the July theory away, and kings will stage in water temps even into the 60s before heading upriver to spawn.
Fishing with a temperature probe in July is key. The first thing you should do in July is send the probe down to see where the break is. Then set the rest of your lures accordingly. I like to run my probe in 51-degree water. You have to keep an eye on it because as you troll the temperature can change. It typically happens in our area if you are either North or South of Big Sauble Point (the change being at the lighthouse in the middle of the point) Or you will see it change as you head to deeper water. Adjust your spread slightly above and below this break.
Lure selection should be primarily spin doctors and meat rigs, followed by spoons. If the fish stop biting switch to all spoons and leave only one flasher down. Typically wire divers are best in the morning and then you will know the bite is slowing down when the fish start taking your long lines on planer boards such as copper or lead core. Spoons on long lines should be your best rods by mid-morning. Plugs will become important if the water warms up. Good luck in July!