Yakima River hatch chart for annual Mayfly, Caddis, Stonefly and Terrestrial hatches. Includes recommended fly sizes and estimated hatch dates. Hatch dates and availability may vary from year to year based on weather conditions, water flows, and whether you’re fishing a tailwater stream (downstream from a dam) or freestone (unimpeded).

The following fly hatch chart for the Yakima River will help you identify some of the more effective fly patterns to fish during different times of the year to match the hatch and improve your catch rate.

Hatches and fly patterns fall into three categories based on the life cycle of aquatic insects in the Yakima River: Nymph/Larvae, Pupae/Emergence, and Adult. Nymph and Emergence fly patterns are designed to match the nymph and emergence stage of a hatch. Dry fly patterns are used to match the adult stage of a hatch.

Yakima River Fly Hatches

The following are descriptions of the major fly hatches along the Yakima River. This list is not all inclusive, but the most important hatches anglers should consider when fishing the Yakima.

Midges

Midge hatches along the Yakima River occur throughout the year. They are at their peak from late spring through early fall, and are one of the more important early season hatches that occur during late winter early spring.

Midge hatches are most abundant along sections of the Yakima where the water is slower moving. When midges mate they form huge clusters on the water’s surface. Fishing a midge cluster pattern (#10-14) is a great way to target large trout during midge hatches.

Skwala Stonefly

The Skwala Stonefly hatch is an early season hatch that occurs from February through March. It is significant because it is the first major hatch that occurs following winter and sets in motion the dry fly fishing season.

There are a large number of Swala Stonefly hatches along the Yakima. It is a hatch anglers should plan for. There are several patterns designed specifically for imitating the Swala Stonefly.

Blue Wing Olive (BWO)

BWO hatches are one of the largest, most abundant fly hatches in the Rocky Mountains, and the Yakima River is no exception. If you want to have success fishing the Yakima, you need to have several BWO patterns in selection of flies.

BWO hatches are one of the first and last hatches of the year on the Yakima. Spring BWO mayflies range in size from 16 to 18. Fall BWO mayflies are much smaller in the 18 to 22 size range. No Hackle BWO imitation flies are most commonly used on the Yakima.

March Brown

The March Brown mayfly hatch is largest and most anticipated hatch that occurs on the main stem of the Yakima each year. It typically begins in mid March and extends through the end of May.

During the peak of emergence, March Brown mayflies cover the surface of the Yakima River. When fishing this hatch you want to use a natural looking imitation fly that float on the surface drag free. Productive patterns include standard March Brown patterns, Para-Wulff Adam’s, and Para-Pheasant Tail in sizes 12 to 14.

Caddisfly

Caddisflies are abundant on the Yakima River and are a major summer food source for foraging trout. Caddis hatches begin in April and extend through late fall. There are several species of caddisflies on the Yakima. The most popular are American Grannom, Little Sedge, and Short Winged Sedge.

Caddis fly patterns should imitate target caddis hatches. Two of the most popular caddis fly patterns are the Elk Hair Caddis and Para-Caddis. If you only have two caddis fly patterns in your tackle, these are the two to have (sizes 14-18). Best caddis fly colors are olive, gray and black.

Salmon Fly

The salmonfly is sometimes referred to as the grand-daddy of all stoneflies because of its size and importance to the fly fishing season on the Yakima. Anglers from far and wide flock to the Yakima for a few short weeks every year just to fish the salmonfly hatch.

The salmonfly hatch on the Yakima gets under way in the month of May and lasts anywhere from 3 to 4 weeks. The exact date this hatch occurs each year, and for how long, depends on the weather and water conditions. The salmonfly hatch starts on the lower Yakima and works its way upstream.

Anglers can fish the nymph or adult stage of the salmonfly hatch. Fishing the nymph stage is often most productive. Bitch Creek and Pepperoni Yuk Bug nymph imitations sizes 6-8 are effective for salmonfly nymph fishing. Wolly Buggers are also effective for fishing salmonfly hatches.

Green Drake

Green Drake hatches occur for a short window in April and May. This hatch is is specific to certain sections of the Yakima River. Green drake hatces are typically most abundant from the Upper Canyon stretch of the Yakia west to Easton Dam.

The green drake hatch isn’t a very high profile hatch but it’s a fun hatch to fish—and the trout respond. Prior to emergence, fishing a short shank nymph such as the Hares Ear is productive. Recommended adult dry fly patterns include Para Drakes, Thorax Green Drake Dun and CDC Thorax Dun. Effective attractors include Royal Wulffs, Grey Wulffs, and Royal Parachutes.

Golden Stonefly

This is a summer stonefly hatch that historically gets underway in June. The size of golden stonefly hatches varies from year to year. Some years hatches are large. Other years they’re almost non existent.

Fishing golden stonefly nymph imitations and streamers just below the surface is often as productive as dry fly fishing on the surface. Bouncing golden stonefly patterns is one of the more effective techiques for fishing this hatch during emergence.

Yellow Sally

This is a small stonefly that hatches in late April through July. The Yellow Sally stonefly is only found along certain stretches of the Yakima. It is most prevelant along the Upper Yakima in the farmland areas. The lower canyons section of the Yakima have historically experienced fewer yellow sally hatches.

This is a great hatch to target on warm summer afternoons when other insects are scarce.

Pale Morning Dun (PMD)

The Pale Morning Dun is one of the major summer mayfly hatches on the Yakima River. It begins in May and can last through July. One of the best patterns for fishing PMD hatches on the Yakima is a simple Parachute PMD size 14-18.

Terrestrials

As aquatic insect hatches subside in late summer, terrestrials including ants, beetles, crickets and grasshoppers take center stage. Terrestrials enter the Yakima scene in late June and remain through early September.

Anywhere you fish the Yakima and there are high, bushy banks the fish will be feeding on a variety of hoppers, ants and beetles. Fly sizes for terrestrials vary betwen 10 and 18.

Light Cahill

The Light Cahill is a mayfly hatch that occurs in late autumn. If you plan on fishing the Yakima between September and October you’ll want to fish patterns that imitate the Light Cahill mayfly.