fly fishing montana in August

Fly Fishing Montana in August

Fly fishing Montana in August means you can leave your tiny bug box at home! When the insect activity of July wanes in mid-August, we turn to our terrestrial boxes and prepare for some of the most exciting fishing of the season.

The water temperatures in August rise and that slows the fish’s metabolism somewhat, but does not in anyway turn off the fishing. August is truly the big bug season with droves of grasshoppers inhabiting the remaining green grass that lines the banks of our favorite Montana rivers. As fly fisherman we generally loath the wind; in August our view of the wind changes and we welcome the warm zephyr. The wind blows these terrestrial insects onto the water and creates a constant interest in these high calorie critters.

August provides the most consistent, big bug, dry fly fishing of the year. As many of the summer hatches have waned, attention turns to terrestrials as a major source of food for trout. hoppers, beatles, & ants – oh my! 

August Fishing Options

The smaller freestones have consolidated from their grand June and July flows and become impassible to the majority of fly practitioners, including other outfitters. We have invested in a fleet of custom built, low water rafts that allow us to navigate rivers like the Boulder and Stillwater with ease and precision. Because almost all of the float traffic has left the smaller Southwest Montana rivers we have the rivers to ourselves and that provides a secluded experience. Additionally, these fish are only seeing natural insects so our imitations are consumed with the appropriate vigor. This is truly a spectacular experience and we have over 60 miles of river to ourselves at this time. While we may have to walk the boat over a couple of shallow gravel bars, the additional reward far exceeds this nominal effort. We almost always fish a single dry to the obvious structure and holding water.

The Paradise Valley Spring Creeks see an exodus of those looking for the larger mayfly hatches and the fish pack into the riffles and begin to look for smaller aquatic insects and the ever present ants, beatles, and hoppers that line the lush creek bank. Those that still seek a “match the hatch” experience can find this throughout the sections of creek that have more sediment as the water temperatures welcome in a small, robust emergence of tricos. The prospects of fishing a size 22 dry fly may seem intimidating to some, but the large white CDC wing is surprisingly easy to pick up on the glassy, creek surface. The spring creeks also see an influx of fish seeking cooler, more oxygenated waters when the Yellowstone River warms.

The Yellowstone River sees a myriad of change in the month of August. The river sees a flattening in flow which sends many other anglers to seek out opportunity elsewhere. However, for those in the know, the Yellowstone River provides top notch fishing throughout the month of August. On the Yellowstone, and other freestones in Southwest Montana, a strong emergence of nocturnal stoneflies is seen. While many have never laid eyes on them, that is because they are flightless and as the name implies – nocturnal. These insects emerge in the morning and skitter throughout the shallow, well oxygenated riffles. In an effort to chase cooler water we often find ourselves on the upper reaches of the Yellowstone where cutthroat and attractor dries dominate the days.

The Madison River provides some of the most oxygenated water in the state, as it truly is one long riffle. The “Fifty Mile Riffle”, as it’s often referred to, sees a decrease in river traffic especially the last week of August. In the meantime there are some secluded sections of river for anglers that enjoy wade fishing. The Madison also provides solid fishing from the boat throughout the month. Like most of the boat fishing we do in August, anglers will find themselves fishing a myriad of attractor dry fly patterns along every bit of structure. 

Private water fisheries continue to produce some of the best fishing the state has to offer. August sees a reduction in their flows and hatch cycle. However, this drives a trout to be more aware of the terrestrial insects that find their way to the water, providing exceptional big bug fishing. Additionally, on some of our higher elevation rivers we see a push of large fish seeking out the coldest, most oxygenated waters. It is something to behold when a 20″ cutthroat rolls off a bank, eats an ant pattern, all in a river that’s 12 feet wide!

August Weather in Montana

In August we see an average high of 82 and an average low of 48 with about an inch of precipitation. August rain is valuable and the days following these events can provide the best fishing of the year.

Montana By The Month

Get a breakdown of what it’s like to fly fish in Montana each month of the year.

Either way you’re in luck – there’s no bad time to go fly fishing in Montana!