June weather, streamflow's, and summary
June on the Missouri River is best divided into two parts, early June and late June. Similar to the Smith River, the first half of June can be good for dry fly fishing and consistent hatches, but the first half of June can also mean high water and the majority of fishing is with two fly tandem nymph rigs with subsurface flies. The second half of June is when the Missouri River shines.
If early June is a wild-card—with a 50-50 chance of being an ace—late June is surely the ace-in-the-hole. By the second half of June streamflows on the Missouri River have stabilized or dropped and hatches of Pale Morning Dun mayflies and caddis are strong. Because streamflows on the Missouri River are regulated by several dams, an understanding of streamflows is crucial to success on the Missouri River in June.
Early in the month as snowmelt runoff continues in rivers and streams at high elevations, the full rivers flow into the reservoirs that regulate the Missouri River’s flows. This causes the releases of the dams on the Missouri River to typically be at their highest outflows in early June. By mid-June outflows, and the resulting streamflows, drop to levels more suited for fly fishing on the Missouri River below Holter Dam. Additionally, the section of the Missouri River below Hauser Dam—known as the Land of the Giants—has the same defining weather and streamflow attributes as the river below Holter Dam.
During June, weather on the Missouri River is often pleasant, yet with the possibility of substantial rain early in the month. Average daily highs in early June are in the low 70 degrees F, but by month’s end increase to high 70 degrees F. Average daily precipitation also increases throughout the month, with the first two weeks of June seeing nearly half the potential of measurable precipitation compared to the last two weeks.
By the third week of June the Missouri River and the small fishing-centric communities of Wolf Creek and Craig are in overdrive. Because the Missouri River is ideally suited for floating and walk-and-wade fishing and home to over 4,000 trout per mile, ample opportunities abound to enjoy its quality fishing. In the second half of June hatches of PMDs and caddis paired with an average trout-size of around 16 inches, the Missouri River has a dedicated following of dry fly anglers in late June.
June fishing: what to expect
June on the Missouri River is about timing things to match with the desired type of fishing. It is fair to have high expectations for quality fishing on the Missouri River in June—water temperatures are ideal for trout, hatches are strong, and the river is full of fish. But the key for fly fishing the Missouri River in June is understanding the differences between early June and late June.
In early June the river is likely to be high, with streamflows over 8,000 cubic feet per second (cfs). There are years these high flows do not occur, but it is best to expect high flows. High flows on the Missouri River do not translate into lousy fishing. It means different fishing than later in June and the lack of the penultimate dry fly bonanza. Early June on the Missouri River is about one thing—catching lots of fish regardless of method.
Two-fly weighted nymph rigs are the go-to rig in early June. Dragging or slowly stripped streamers can also catch some fish, but weighted worms, mayfly, and caddis nymphs fished in slower water are the preferred method for filling the net. As streamflows rise or a rain event occurs—which is common in early June—many longtime Missouri River anglers embrace fishing worm patterns. Worms are flushed into the currents during rising flows or rain events. A successful rig for the Missouri River in early June is size 10 worm pattern and a size 16 beadhead Pheasant Tail, caddis, scud, or sowbug.
The payoff for fishing non-conventional methods in early June is the world-famous dry fly fishing that occurs in the second half of June. As the flows from snowmelt runoff make their way through the Missouri River’s reservoirs and outflows drop, the focus on the Missouri River below Holter Dam changes from a numbers game of subsurface nymphing to a sight-fishing game of matching the hatch or finding the “pods” of rising trout.
Caddis and Pale Morning Dun (PMDs) have strong emergence in late June on the Missouri. Look for fish to actively feed on emerging and hatching insects once flows drop below 8,000 cfs. At levels below 6,000 cfs wading anglers can begin to pursue these hatches.
PMDs dry flies and emergers in sizes 14 through 18 fished in riffles and shallow flats are preferred and caddis dry flies and emergers in sizes 14 through 16 fished in similar habitats should entice fish.
Where to find June trout on the Missouri River
Where trout will be found in June depends on streamflow and available hatches. For the first half of June flows traditionally can be high while by the second half of June flows will begin to drop and by the last week, they are often below 6,000 cubic feet per second (cfs), slipping right into the prime dry fly range.
In early June if streamflows rise above 10,000 cfs many of the river’s trout will migrate to feed in the softer water—inside bends of islands, slower deeper runs below long shelfs, or slow currents of large eddys. During high flows or after a rain event, worms--both aquatic and land-based--can be flushed into the river. Many longtime Missouri River locals know this and when this occurs the fishing of worm patterns is very successful.
In early June, if the river has rising flows, target slow eddys, foam lines, and any soft water near structure with subsurface nymphs. Trout will be in lies where they can enjoy access to food floating by without spending too much energy swimming in the rising streamflows. Trout will also hold and feed in the large seams created by the many large protruding rocks that are prominent on the Missouri River. Trout use these slower, mixing currents, as both holding and feeding lies. Two-fly subsurface nymph rigs can rack up trout numbers in these current seams.
Even in high flows caddis hatches can be thick. If flows are high fish will hold and feed in softer water. If flows drop below 6,000 cfs and if caddis hatch, look for trout in faster, shallow areas of the river. Target water with a stream bottom made of small rocks or pebbles or seams along many of the large cliffs and rock shelves that protrude into the water.
Long, shallow flats are common on the Missouri River. Many of these flats are dotted with weed humps and potholes, both creating structure and cover for trout. When streamflows are below 4,000 cfs and during a caddis hatch these flats can be filled with rising trout.
Pale Morning Duns (PMDs) hatch in mid and late June on the Missouri River. These hatches can be very strong and many of the river’s trout will move to shallow flats, riffles, and runs to feed on emerging nymphs or floating adults. Look for trout in faster currents along riffle corners and seams, medium-speed currents on shallow flats or long runs, and as the hatch wanes later in the day look for eddys where PMDs adults may have stacked-up.
When hatches of PMDs and caddis are thick, look for Missouri River trout to group up in “pods” in the various feeding lies. A well-presented dry fly through one of these pods may entice a strike.
Important June hatches
Hatches of Pale Morning Duns (PMDs), caddis, and Drakes can occur in June. PMDs and caddis are the stars of the show in June on the Missouri River. With the Missouri River’s abundance of long riffles and shallow flats and a streambed of cobble-sized rocks and weed humps, the river is home to ideal habitat for PMDs and caddis.
Caddis can hatch early in June and last throughout the month. Emergences can be very strong and with dozens of species of caddis in the Missouri River, trout have plenty of insects from which to choose. Most caddis on the Missouri River are sizes 14 through 18.
In some years, PMDs can hatch in early June, but they are more common to begin in the later part of the month. Emerging out of riffles and flats, these size 14 to 18 mayflies create ample opportunities for floating and wading anglers.
Yellow Sally stoneflies also hatch in June. Trout will consume the nymphs—especially in the canyon section of the river between the Dearborn Confluence and Prewett Creek—but rarely do Missouri River trout eat Yellow Sally adults.
Worms—both aquatic and terrestrial based—are abundant on the Missouri River. These worms do not hatch like mayflies or caddis, but after a large rain event or rise in streamflows, these worms are dislodged and become easy pickings for trout.
Missouri River fly box for June
Caddis pupae size 14 to 18
Caddis CDC emergers size 14 to 18
Caddis dry flies with dark grey, black or brown bodies in size 14 to 18;
PMD dry flies size 14 to 20
PMD emergers size 14 to 20
PMD nymphs size 14 to 20
Drakes, brown and green, dry flies in sizes 12 or 14
Yellow Sally nymph in sizes 10 and 12
Worms in sizes 8 through 14
Scuds in sizes 10 through 20
Sowbugs in sizes 10 through 20
Midges, especially Zebra midges in black and olive, in sizes 16 through 22
Sculpin patterns in sizes 2 to 6
Streamers in olive, black or brown in sizes 2 to 6