Yellowstone River Fishing in April

Fly Fishing the Yellowstone River in April

As snowpack melts along the valley floors, the Yellowstone River begins to awaken in March and early April with increasingly active trout. The lower stretches of Paradise Valley are teaming with increasingly active Rainbow Trout, preparing for their spring spawning season.

The mouths of Nelson’s and Depuy’s Spring Creeks see particularly heavy concentrations of Montana fish.

Montana fishing conditions are unpredictable throughout early spring on the Yellowstone River. Low-elevation snow and heavy rains can cause river levels to rise and water clarity to quickly diminish.

Cool temperatures throughout April will keep the river in great shape right up until the start of the runoff in early May.

Consistent Spring Hatches

Blue-winged olive mayflies and Midges are active in April. March Browns and Caddis emerge later in the month as spring finally arrives in Montana. The Mother's Day Caddis Hatch generally begins in late April or early May.

Fishing the Mother’s Day Caddis Hatch on the Yellowstone River

The Yellowstone River experiences a Caddis hatch near Mother's Day, which is considered the best among all similar hatches in the western US. The river's surface is covered with unimaginable rafts of these hatching insects, making fishing fantastic.

However, there is a downside to this hatch.

Typically, the Mother's Day hatch starts in late April as the weather warms up and daytime temperatures reach the high 70's or even low 80's. This leads to the melting of snow in the surrounding high country, which accelerates when the nighttime lows stay above freezing for a few days.

As a result, the river swells in volume and loses its clarity, usually between the last week of April and the second week of May.

Based on our 23+ years of guiding Yellowstone River fishing trips, the more likely scenario is that the weather will gradually warm up, reaching into the 70's or 80's for a few days.

The Caddis will start to emerge, but a cooling event will slow the hatch and keep the river clear for another week or two following the initial emergence.

After this, the hot weather will return, the hatch will explode, and the fishing will be amazing for a few days before the runoff reaches the Paradise Valley stretches.

In this scenario, anglers can expect good fishing once the Caddis arrive, with some days being exceptional, both on dries and dry/dropper rigs for these two weeks.

Early Season Techniques

As with most regional waters in Southwest Montana, early-season fishing centers on dead drift nymphing and stripping streamers. Expect to employ varied techniques, adjusting approaches to capitalize on changing conditions daily.

Floating fly lines will cover the angler for all aspects of Yellowstone River fishing in April.

Standard nymph setups include tandem rigs with added split shot, fished about 6 feet under a strike indicator. Switch to dries when hatches begin, looking for rising fish on the insides of gentle seams and eddies.

Articulated streamers - in light colors - fished near undercut banks and along gravel-bar drop-offs elicit more and more strikes as the weather warms.

Bozeman Fly Fishing Guide Pro-Tip:

Fly fishing Montana's famed Yellowstone River during April can be epic. Fish are eager to feed as the temperatures warm, providing great angling opportunities using nymphs, streamers, and dry flies. Between Emigrant, MT, and Loch Leven FAS, targeting foam eddies using BWO nymphs below an indicator with a high stick approach can be very successful.

Our Yellowstone River Fly Box for April