June Fishing on the Jefferson River

June weather, stream flows, and summary

June on the Jefferson River is a lesson in split personalities. Early June often sees the river high, muddy, and unfishable. But that can quickly change by the middle of June, if not earlier. When this shift occurs, there’s a few weeks of fishing the Jefferson River in June that sees action rivaling some of Montana’s best rivers. The kicker—knowing when- and being able- to be in the right place at the right time. 

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 out-weigh 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. 

The first week of June sees stream flows averaging around 5,000 cubic feet per second (cfs). At these flows the river is unsafe for floating and walk-and-wade fishing. In years that see lower stream flows, floating and fishing is viable. By mid-June stream flows begin to drop, making fishing more viable and in most years the last week of June sees stream flows quickly dropping to fishable levels. 

June fishing: what to expect

Fly fishing in June on the Jefferson is quite unique. Once the river drops and becomes fishable, streamer anglers find plenty of big fish on the move, and number-crunchers can find some success with subsurface weighted two-fly nymph rigs, particularly large stoneflies, crayfish, or worm patterns. However, like many rivers in Montana during June, patience is paramount because snowmelt runoff peaks this month…the challenge is knowing when that will occur.

Depending on flows and clarity, a typical day in early June will be entirely different than later in June. Early June has most anglers fishing weighted two-fly nymph rigs. Choose one stonefly nymph in sizes 4 through 8 and one worm pattern in size 8 or 10. Hatches of caddis may occur early in the month, however stream flows and clarity will determine viability of fishing the hatch. 

As snowmelt runoff begins to subside typically sometime between June 15th and 20th, the fishing transitions from exclusively subsurface to dry fly friendly. Sporadic hatches of salmonflies can occur in mid-June. From the start of these sporadic salmonflies, anglers will see hatches of Golden Stoneflies, caddis, and Pale Morning Dun (PMDs) mayflies. Most successful days begin fishing weighted two-fly nymph rigs below a strike indicator. As stonefly and PMD nymphs become more active, a dry dropper rig will begin to catch fish. Fishing a size 6 through size 10 high-floating dry fly and a size 8 through 12 weighted nymph is useful. 

Where to find June trout on the Jefferson

Jefferson River trout cover a variety of habitat during June. Early in the month most trout will be found along banks or structure near the banks and near any logs, rocks, or other middle-of-the-river structure. 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 PMDs begin to hatch, often in the later third of the month, stream flows are lower and trout can now hold in riffles, runs, near mid-river shelfs, and even on shallow flats. On the Jefferson in June during a PMD 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 mayflies. 

Because fly fishing the Jefferson in late June sees such a variety of hatches, trout are found in a variety of habitats. It sounds simple to stay, but the best place to find trout on the Jefferson in June River is pretty much anywhere that stoneflies, PMDs, or caddis are hatching. 

Important June hatches

Salmonflies can hatch around June 15th on Jefferson River.  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 Jefferson River, but it is a mayfly that is the cause of so many great fishing days of dry fly fishing on the Jefferson River in June. Pale Morning Duns hatch in abundance on both the Lower and Upper Jefferson Rivers. Ranging in size from 12 to 16, PMDs in the Jefferson River make up the majority of a trout’s diet during June. 

Jefferson River fly box for June

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

Salmonfly dry flies in sizes 4 to 8

Golden stonefly dry flies in sizes 8 and 10

Yellow Sally nymphs in sizes 10 to 16

Yellow Sally dry flies in sizes 10 to 16

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; 

Crayfish patterns in sizes 2 to 8

Worm patterns in sizes 6 to 10

Sculpin patterns in sizes 2 to 6

Streamers in olive, black or brown in sizes 2 to 6