Southwest Montana Fly Fishing Forecast: What to Expect This Summer
If you’re dreaming about long casts, rising trout, and the smell of sagebrush on a warm breeze, you’re not alone. Fly fishing season in Southwest Montana is here!
As fishing guides, one of the questions we get asked the most is: “What will the fishing be like when I’m there?”
We wish we had a crystal ball—but here’s the truth: predicting weather and fishing conditions in Southwest Montana is never an exact science. Mountain weather changes fast, and river conditions can swing overnight. And while we can’t predict the weather or fishing conditions with total accuracy, we can help paint a picture of what a typical season looks like, and what’s shaping up for summer 2025.
Runoff Update: A Faster Start, A Sooner Finish
As of early June 2025, runoff is already close to peak across much of Southwest Montana. Due to a warmer-than-usual spring, snowmelt hit earlier and faster than most years. This means many of our freestone rivers—like the Gallatin, Yellowstone, and even tailwaters like the Upper Madison—will clear up quicker and should be fishing sooner than in typical seasons.
Factors like cooler weather and rain can prolong runoff. If we get any cold/wet spells this can mean a longer runoff.
Here’s what that means for you:
Gallatin River: should come into shape earlier this year. We expect fishable conditions by mid to late June. Expect Salmonflies late June/early July
Yellowstone River: Usually not ready until early July, but keep an eye out—this year clarity could improve fast. We may see floatable, fishable days by late June.
Upper Madison: As a tailwater, it stays relatively consistent. It’s already producing with nymphs and streamers and will shift into salmonfly mode soon.
Lower Madison: A Consistent early summer fishery, not effected by much tributary runoff. The “Bikini Hatch” has started, get out early to avoid the tube crowd.
If you’re planning a trip, mid-to-late June could offer earlier-than-usual access to rivers that are typically blown out until July.
Summer Hatches: What to Expect and When
While the weather and river conditions can shift quickly, this year’s early snowmelt suggests an earlier start to dry fly fishing, and a head start on some of Montana’s best hatches:
Salmonflies (Late June – Early July): The big bug everyone waits for. Expect them a little bit early this year. With runoff ending early, they could pop in mid-to-late June this year.
Golden Stones (Late June – Mid-July): Slightly smaller than salmonflies, but just as exciting. Great hatch right after Salmonflies.
PMDs (Pale Morning Duns) (Mid-June – July): A summer staple. These offer consistent dry fly action on the Madison and spring creeks like DePuy’s and Armstrong’s.
Caddis (June – August): Especially strong in the evenings. Tan and olive-bodied caddis are reliable all summer long.
Terrestrials (July – September): Ants, beetles, and hoppers become key as summer progresses. Hopper season often ramps up after July 15, peaking in August.
Planning Your Bozeman Fly Fishing Trip
With rivers clearing early and hatches beginning soon, now is a great time to plan your fly fishing trip to Bozeman, MT. Whether you're chasing trout on the Madison River, exploring the scenic Gallatin Canyon, or floating the Yellowstone, summer 2025 is shaping up to be one for the books.
Need help planning? If you’re ready to fish or have questions about timing, gear, or booking a trip, reach out to us. We’re always happy to talk trout.
Ready to Fish Southwest Montana?
Book a guided fly fishing trip with us and experience incredible fly fishing across Montana’s legendary rivers.
See ya on the water!
