Summer musky are active but spread out, which makes them both exciting and frustrating. On this how-to episode of the Fly Fishing Insider Podcast, Dan Donavon of Musky Fool walks through how he approaches the season in Wisconsin water. Here is the game plan as I understood it.

Start aggressive and let the fish adjust you
Dan's summer bread and butter is a full intermediate line on a 10 or 11 weight, moving up to a 12 weight later in the season. When he arrives on new water without inside info, he starts with a natural-colored fly and strips it back to the boat quickly. The idea is to cover water and find an aggressive fish, then adjust depth and speed as the fish respond. Because summer musky are spread out, he is happy to fish a whole day this way, accepting follows and figure eights as information.
Fly size and topwater
He keeps flies average in summer, around nine to twelve inches. If he could carry only two styles, he would choose a bushy buford-style fly for its walk-the-dog action and a streamlined minnow pattern he can burn back fast. Topwater is a major summer window: poppers, sliders and a block-of-foam style pattern that pushes water. Dan likes black topwaters for the silhouette against sky or moon, and says that noise matters more than size. A favorite trick is fishing a buoyant topwater on an intermediate line. The line pulls it under on each strip, and it pops back up, making a loud, attractive disturbance.

Where the fish are
On rivers, work every kind of water on your list: timber, weed pockets, mid-river structure, bends, deep holes and pocket water. In summer Dan notes musky are more often behind boulders in fast current than in other seasons. On lakes, weeds locate fish. In the tannic Wisconsin lakes he describes, he follows fish from shallow lily pads, milfoil and cabbage out to weed edges, especially thick edges near rocky drop-offs or necked-down water. He fishes from about 15 feet of water all the way into the shallows, and reminds us early summer fish can be tight to cover in a couple of feet of water.
Water temperature as a guide
Dan starts fishing seriously in spring around 55 degrees, enjoys the 60s and low 70s, and notes fish get lethargic near 77 degrees as dissolved oxygen drops. He gives them a break when water reaches 80. In late fall, below 40 degrees, fish are easy to locate but sluggish, so expect multiple follows before one eats.
Never skip the figure eight
His most repeated advice: if you are not doing a figure eight, you are missing fish. Even on day two of a float, execute the figure eight perfectly after every cast, because the moment you relax is when the fish shows up.
Gear
Muskies call for solid heavy-rod technique, and the Tips and Tricks for Fly Fishing eBook covers rigging basics. Keep the sun off on long boat days with the Five Panel Cap. For a 10 to 12 weight rod and intermediate line, a local fly shop can match a setup to your water.