June Fishing on the Big Hole River

June weather, stream flows, and summary

A fly fishing trip on the Big Hole River in June is not to be taken lightly—because in most years June on the Big Hole River is the month local anglers and Big Hole River loyalists look forward to each year. By the second week of June, and in some years earlier, the river drops and clears after snowmelt runoff. Along with the ending of snowmelt runoff comes an abundance of hatches…most notably salmonflies and Golden stoneflies and then transitioning to caddis and Pale Morning Dun mayflies. 

Dropping flows paired with ideal water temperatures and a plethora of hatches, rarely is a day of fly fishing the Big Hole River in June a disappointment. The biggest draw during this time of year is the famed salmon fly hatch which generally runs for a three week stint in June. These large insects—many of them over 2-inches long—cause Big Hole River trout gorge themselves. The hatch starts in the lower stretches near Glen and works its way upstream. Each day salmon flies make their appearance a little further up the river. The location of the emergence is not an exact science and sometimes it moves only a fraction of a mile in a day, while at other times it can move quickly covering multiple miles a day.

After salmonflies hatch, Golden stoneflies, caddis, Yellow Sally stoneflies, and Pale Morning Dun (PMDs) mayflies can hatch in strong numbers on any day. Water temperatures range from 55 degrees F to 65 degrees F, which is the ideal range for actively feeding trout. With a diverse and abundant cornucopia of hatching insects, June fly fishing on the Big Hole River covers all the bases.

During early June most fishing on the Big Hole River is done with boats. As the river drops and walking-and-wading becomes safe and effective, anglers can enjoy the Big Hole River’s variety of hatches on foot. 

Much like the fishing, the weather in June is varied. Early June sees average daily high temperatures hover around 70 degrees F while later in the month average daily high temps tick close to 80 degrees F. Later in the month the prevalence of sunny days far outweighs overcast days. These warmer and drier days mean more comfortable fishing conditions. The warmer and sunnier days coupled with a river that is poised and primed for salmonflies, Golden stoneflies, and PMDs make the Big Hole River one of Montana’s most consistent fisheries during June. 

June fishing: what to expect

June on the Big Hole River is truly the stuff of angling legends. Resisting hyperbole is difficult on this river during June because with dropping stream flows and an abundance of hatches, anglers can expect a river in prime conditions. 

Fly fishing in June on the Big Hole River is quite unique. Many years the river fishes differently in early June compared to later in the month. In most years, mountain snowpack is still melting the first week of June, but on any day in early June the river’s stream flows can drop and improve in clarity to make fishing viable. 

In some years snowmelt runoff can continue into the middle of the month, but on average by June 10th stream flows are dropping and it is time to fish the Big Hole River. Depending on flows and clarity, a typical day in early June will be entirely different than later in June. Early June has anglers hoping for salmonflies to hatch but realistically they are fishing weighted two-fly nymph rigs. Choose one stonefly nymph in sizes 4 through 8 and one prospecting nymph such as a Pheasant Tail or Prince in sizes 10 or 12. 

Anglers desiring to tag into some of the Big Hole River’s trophy-sized brown trout will want to drag, dead-drift, or slowly strip large streamer patterns. Choose white, yellow, or a dark-and-light contrasting colored streamers. Many veteran Big Hole River guides also use a strike indicator as this helps to float the larger streamer while dead-drifting to avoid snagging structure and losing a fly. 

As snowmelt runoff begins to subside typically sometime between June 10h and 15th, the fishing transitions from exclusively subsurface to dry fly friendly. Hatches of salmonflies begin on the river near Glen and migrate upstream to the North Fork to Dewey sections. When this occurs anglers can fish large dry flies with stonefly nymph droppers. From the start of the salmonfly hatch and through the remainder of June, anglers will see hatches of Golden Stoneflies, caddis, and Pale Morning Duns (PMDs). Most successful days begin fishing weighted two-fly nymph rigs below a strike indicator. 

As stonefly, caddis, and PMD nymphs become more active, a dry dropper rig will begin to catch fish. Fishing a size 4 through size 10 high-floating dry fly and a size 8 through 12 weighted nymph is useful. Depending on the hatch—stoneflies, PMDs, or caddis—opting for a single dry fly and targeting specific water can be quite a fun way to enjoy June dry fly fishing on the Big Hole River. Target the banks or mid-river structure if stoneflies are hatching and target riffles, shelves, and runs if caddis or PMDs are out. 

Because the Big Hole River flows for nearly 150 miles, the various sections will fish a little different in June. Caddis dominate the upper sections above Dewey to Wisdom while stoneflies dominate downstream of Dewey to Glen. PMDs and caddis are also prevalent from Dewey to Glen. Downstream of Melrose onto the confluence with the Beaverhead River near Twin Bridgers, anglers targeting big fish may find them with a well-presented streamer rig. 

Where to find June trout on the Big Hole

Because the Big Hole River flows for nearly 150 miles and an abundance of hatches occur in June, Big Hole River trout cover a variety of habitats.  June is the kick-off to the summer angling season and in most years the river is fishable by June 10th, if not a few days earlier. 

While salmonflies and stoneflies dominate the hatches in the first half of June, most trout will be found along banks or structure and near any logs or rocks along the banks. Because stoneflies hatch by clinging to structure and then emerging from an exoskeleton, trout follow the insects and become opportunistic feeders as the current washes away the structure-clinging nymphs. Additionally, the high and fast stream flows so common early in the month necessitate trout hold near structure to gain a respite from the strong current. 

When Pale Morning Duns (PMDs) and caddis begin to hatch in the second half of June, stream flows are lower and trout can now hold in riffles, runs, near mid-river shelfs, and even on shallow flats. On the Big Hole River in June during a PMD or caddis emergence, trout can be found at the tail end of a shelf or riffle gorging themselves. They can also be found on a shallow flat sipping adult caddis or mayflies. 

It might sound like an over-simplification, but the best place to find trout on the Big Hole River in June is pretty much anywhere that stoneflies, PMDs, or caddis are hatching. Because fly fishing the Big Hole River in late June sees such a variety of hatches, trout are found in a variety of habitats. 

Important June hatches

The salmonfly hatch steals the headlines for the Big Hole River’s June hatch chart. But it is not the only hatch, and in some years the salmonfly hatch can come and go during runoff with high flows and muddy water not allowing for fishable conditions. 

The timing of the hatch varies from year to year, but most years these insects hatch between June 10th and June 20th. They are often first spotted around Glen and migrate upstream as water temps warm and clarity improves.   

After salmonflies, Golden stoneflies and Yellow Sally stoneflies hatch, creating even more large dry fly fishing opportunities. Salmonflies and Golden stoneflies may get the most attention of June hatches on the Big Hole River, but mayflies and caddis eventually ride out the month and are the cause of so many great fishing days on the Big Hole River in June. 

Pale Morning Duns (PMDs) hatch in abundance on the entire river from the North Fork to its confluence with the Beaverhead. Ranging in size from 12 to 16, PMDs in the Big Hole River make up a large portion of a trout’s diet during June. 

Caddis also hatch in abundance in June on the entire run of the Big Hole River. Ranging in sizes from 12 to 18, caddis can emerge in large numbers early in the month and increase in frequency as stream flows drop and water temps rise to the magical 56 degrees F mark. 

Big Hole River fly box for June

Salmonfly dry flies in sizes 4 to 8

Golden stonefly dry flies in sizes 8 and 10

Caddis pupae sizes 14 to 16

Caddis CDC emergers sizes 14 to 16

Caddis dry flies with dark grey, black or brown bodies in sizes 14 and 16; 

PMD nymphs sizes 14 to 16

PMD emergers sizes 14 to 18

PMD dry flies sizes 14 and 16

Stonefly nymphs in brown and black in sizes 4 to 10

Yellow Sally nymphs in sizes 10 to 16

Yellow Sally dry flies in sizes 10 to 16

Crayfish patterns in sizes 2 to 8

Sculpin patterns in sizes 2 to 6

Streamers in white, yellow, or light-and-dark contrasting colors in sizes 2 to 6