June Fishing on the East Gallatin River

June weather, stream flows, and summary

Fly fishing the East Gallatin River in June is an exercise in patience. Early June often sees the river high, muddy, and unfishable. Because fishing from a boat is not allowed and nearly all of the river flows through private property, walking and wading the East Gallatin River in June without trespassing is challenging.

As stream flows drop throughout the month, and in most years by the last week of June, walking-and-wading anglers can be able to fish and stay in the streambed without being concerned about trespassing—the East Gallatin River is notorious for landowners harassing walking-and-wading anglers who have legally gained access.  

Much like the fishing and the ability to fish the river, 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 temperatures are close to 80 degrees F. Later in the month the prevalence of sunny days far out-weighs overcast days. These warmer and drier days mean more comfortable fishing conditions, but stream flows are often still too high to reasonably walk-and-wade. 

The first week of June sees stream flows averaging around 300 cubic feet per second (cfs). At these flows the river is very hard to walk-and-wade and stay below the mean high-water mark, plus it is borderline unsafe for walk-and-wade fishing. In years that see lower stream flows, 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 levels below 150 cfs. At these flows walking and wading angling without trespassing is possible. 

June fishing: what to expect

The fishing—and whether or not it can happen—on the East Gallatin in June is all about stream flows. In most years being able to safely and legally—do not trespass on the East Gallatin as you will get caught and the landowner will make your life difficult—doesn’t occur until the last week of June. When it drops below 150 cubic feet per second (cfs) walking-and-wading is viable and the fishing can be quite good with Pale Morning Dun (PMDs) mayflies, caddis, and streamers. 

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 8 or 10 and one worm pattern in size 10. Hatches of caddis may occur early in the month however stream flows and clarity will determine viability of fishing any hatches. 

As snowmelt runoff begins to subside, typically sometime between June 15 and 20th, the fishing transitions from exclusively subsurface to dry fly friendly. 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 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 East Gallatin

When flows are above 200 cubic feet per second (cfs) trout on the East Gallatin River are hard to find. Early in the month most trout will be in slow water found along banks or structure near the banks and near any logs, rocks, or other middle-of-the-river structure. 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 Dun (PMDs) mayflies 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 East Gallatin in June during a PMD emergence, trout can be found at the tail end of a shelf or in a riffle gorging themselves. They can also be found along a slow bank slowly sipping floating adults. 

Because fly fishing the East Gallatin 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 East Gallatin in late June River is pretty much anywhere that PMDs or caddis are hatching. 

Important June hatches

June hatches on the East Gallatin are not as varied as other area rivers, but for the two main species of aquatic insect—caddis and Pale Morning Dun (PMDs) mayflies—the hatches are strong and the trout respond.  Pale Morning Duns hatch in abundance on the East Gallatin from Bozeman to where it meets the main Gallatin River north of Manhattan. Ranging in size from 12 to 16, PMDs in the East Gallatin River make up the majority of a trout’s diet during June. Caddis range in size 14 to 18 with most being size 16. 

Yellow Sally stoneflies also have strong hatches on the East Gallatin River in June. Most are size 10, however because adult Yellow Sally stoneflies have such sporadic flying habits, trout rarely feed on adults but feed regularly on Yellow Sally stonefly nymphs. 

Worms—both aquatic and land-based—are abundant on the East Gallatin River in June. Any angler who doesn’t mind fishing subsurface should consider fishing a size 10 worm as part of any two-fly nymph rig. 

East Gallatin River fly box for June

PMD nymphs sizes 14 to 16

PMD emergers sizes 14 to 18

PMD dry flies sizes 14 and 16

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 grey, tan, 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