A Guide to Fishing the Smith River in May

Fly fishing the Smith River in Montana in May

Posted by PStraub

The Smith River is Montana's penultimate overnight river camping and fishing trip. The primary fishing season on the Smith River runs from late spring through early summer, and then again in September and October. Of all the months of fishing on the Smith River, May is the most dynamic. With pre-, during-, and possibly post- runoff fishing all occurring in May, fly fishing the Smith River in May can be some of the best of the season. With proper planning and the right attitude, a fly fishing trip in May on the Smith River can be one of the best trips of the year. Even though fishing is often the focus of the trip, the scenery and the overall high-quality experience often outmatch the consistently good fishing. The river's unique management system has created one of the West's most coveted overnight camping and floating trips, but even with this carefully managed wild trout fishery, understanding the moods and methods of the Smith River requires substantial knowledge. Here is our Guide to Fishing the Smith River in May.

The Smith River in May can fish well despite being muddy and on the rise. — The Smith River is one of Montana's most consistent freestone rivers during the month of May. Even when streamflows are high and the river is muddy, trout on the Smith River feed on the abundant insect life. May is a month of variable conditions on the Smith River, but rarely is the river unfishable.

Runoff or Pre-Runoff?
When thinking about planning a trip in May on the Smith River, hatches of Blue-Winged Olives, caddis, and stoneflies immediately come to mind. But, just as quickly as the Smith River in May can be a massive buffet of prolific hatches, localized weather can result in the start of snowmelt runoff. Or, the weather in May can be relatively consistent, and snowmelt runoff doesn't factor into a fly fishing trip on the Smith River. May on Montana’s remote Smith River is a month of variety of fishing action, weather, and streamflows. Featuring a range of daily high temperatures, fishing conditions follow suit and change rapidly. For many Smith River veteran anglers, May is the favorite month of the angling season. However, if snowmelt runoff commences or large amounts of precipitation fall, causing a rapidly rising river, it may be a few days before the trout adjust and resume prolific feeding habits, but that doesn’t mean they cease feeding—Smith River trout continue to feed in conditions deemed unfishable on many other rivers.

Fly fishing the Smith River in May with Montana Angler — The first few weeks of May on the Smith River are often before snowmelt runoff begins. Hatches of caddis can be abundant during these few weeks, but even if hatches are minimal, trout on the Smith River will feed on the many large nymphs, sculpins, and other insects,

Early May
In most years, early May on the Smith River is pre-runoff. The Smith River is unique when compared to many of Montana's other freestone rivers. Even when not in runoff, the Smith River runs muddier than most rivers, but it doesn't affect the fishing because Smith River trout are used to dirty water. The toughest conditions in May occur when the river is rising rapidly, due to hot weather or heavy rains commencing runoff. In the first half of May, moderate increases in river flows occur regularly and are generally tolerated well by the trout. It can be a great time to fish if the Mother's Day caddis hatch is happening. If the river is rising fast and gaining hundreds of cubic feet per second of added discharge from one day to the next, trout are forced to adjust their feeding lies, and they become harder to find. Year-in and year-out, predicting these rapid increases in flows on the Smith River is nearly impossible, but in most years, the transition from pre-runoff to full-on runoff mode can occur at any point during the month of May.

Fishing the Smith River in Montana in May — The middle few weeks of fishing on the Smith River in May can mean a variety of conditions. Anglers can expect a river that is either rising or dropping depending on localized weather patterns. One thing that is constant in May is the Smith River will almost always be off-color. This doesn't affect fishing on the Smith River compared to other freestone rivers.

Mid May
The middle ten days or so of May can be some of the best times on the Smith River to find large trout. Even if flows are gradually rising, the amount of food available to trout is some of the most abundant of the year. As hatches of salmonflies and Golden stoneflies begin, the nymphs become more active. The Smith River's large populations of crayfish also provide a large amount of food for hungry trout. Additionally, because May in Montana is one of the wettest months of the year, many land-based insects can also be found in the river, such as earthworms. A worm is a large chunk of fat and protein for a trout, so if you plan to fish in May on the Smith River, be sure to have some worm patterns in your fly box. If a large ran event occurs in mid-May, flows can rise rapidly. This may cause the fishing to slow down for a day or so as the trout adjust to higher flows, but rarely does the river become so high that it is unfishable.

Montana Angler Smith River trip in May — By late May, the Smith River is often on the drop and clarity is improving. A localized rain event can cause the river to rise temporarily and cause it to be off color, but by late May runoff is typically over and the trout begin to move back to feeding along the majestic cliff walls.

Late May
By late May, the Smith River snowmelt runoff has typically peaked, and flows stabilize or gradually begin to drop. Snowmelt runoff can last several weeks, and in some years, runoff hasn't fully subsided until mid-June, but because Smith River trout feed in water that is deemed dirty by most standards, the fly fishing in late May on the Smith River is rarely affected by snowmelt runoff. Similar to earlier in May, a large rain event can cause the river to rise rapidly. Persistent anglers can find fish in these challenging conditions, but within a few days, the river begins to drop again, and hatches of caddis and stoneflies commence again. In some years, late mean is the ideal time for dry fly anglers because salmonflies are abundant along with caddis and stoneflies; but in some years a prolonged or late snowmelt runoff doesn't begin until late May, but because Smith River trout feed in dirty water and gradualy rising flows, anglers on the Smith River can still find plenty of trout using subsurface tactics.

Knowing where to cast your fly on the Smith River is about reading the water. The Smith River is filled with excellent trout water--sometimes it is hard to choose where is the best place to cast your fly. During May, trout will follow the food and this can change from week to week on the Smith River.

Reading Water in May
The water to target in May depends entirely on the condition of the river. During May, rising flows and muddy water can be quite common, but Smith River trout feed in muddy water. In fact, some of the best fishing on the Smith River occurs during times of muddy water, so rarely does a day exist in which trout cannot be found. In most conditions, target the currents along the towering canyon walls, but during the higher—and often rising flows—of May, most of the Smith River’s trout prefer the slower water downstream of a canyon wall or the soft inside bend across the river from the faster current along the wall. If hatches of salmonflies, Drakes, or caddis occur, trout can be found near bank-side structure and foam lines created by mixing currents or other structures. In these slower waters, look for rising trout. During a hatch of caddis or Drakes, target slower currents, eddy lines, and seams behind rocks. For salmonflies, focus on bank-side structure, willows, eddylines, and foamlines. If a hatch doesn’t occur and the river has rising flows and muddy water, target slow eddies, 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 heavy, rapidly rising streamflows.

During May on the Smith River prolific hatches can occur. On any given day in May it wouldn't be too far fetched to see caddis, mayflies, and stoneflies all hatching. In most years, Blue-Winged Olives can be seen in early May, followed by Mother's Day caddis, followed by Drakes, and rounded out with salmonflies and Golden stoneflies.

Hatches and Flies for May
May can be a busy month for insect activity on the Smith River. Anglers on the Smith River in May hope to find hatches of salmonflies and caddis. The famous salmonfly hatch happens earlier on the Smith than on other Montana waters, with the peak of the emergence in mid-May. Dry-fly fishing over the salmonfly hatch depends on the stability of the flows, though. Oftentimes, the water temps that coincide with the hatch sync with rising flows, so trout are usually targeting the large nymphs. On days where the weather is cool but stable and still warm enough to keep the hatch going, lucky anglers can experience some amazing dry-fly fishing by casting huge foam patterns along the cliff walls. Early in May, the Mother’s Day caddis hatch can occur in the same timeframe as its namesake. Unless above average temperatures or above average rain occur, the Mother’s Day caddis hatch is a reliable early May hatch. In addition to salmonflies and caddis, May hatches on the Smith River include Golden stoneflies, Yellow Sally stoneflies, a few Blue Winged Olive mayflies, and Brown and Green Drakes.