May in Big Sky Country is a magical month. The trees are full of buds, the grass is green, the mountains are still white, and the fish are feeding. May marks a season of change in Montana. Spring and summer both readily characterize the weather observed in May, with sunshine, snow, rain, wind and calm all possible on the same day. While the weather can show a hyper level of variability, often times we see consistently nice weather with a day or two of precipitation mixed in. To make the fishing even more interesting, May, June, and early July represent the time period where a lot of western trout will put on as much as 50% of their annual mass. Needless to say, the fish are feeding with fervor at this time period.
The first half of May often provides the greatest diversity of fishing opportunities. From freestones to tailwaters nearly every river in southwest Montana provides at least one exceptional angling day in early May. Hatches abound and emergences of beatis, march browns, Mother's Day caddis, and midges can all be encountered. The Mother's Day caddis is a spectacle rivaled by only a few mayfly emergences like sulfurs on the Delaware. Innumerable insects mill along the banks in the mornings and evenings and the trout readily feed on them from pupae to egg layer. March browns are large mayfly common to our cobbled western rivers. They emerge rapidly shedding their nymphal shucks on the bottom and ascending to the surface. Swung fly presentations can be deadly in waters that contain these neat mayflies. Baetis (BWO’s to some) are a small mayfly that provide consistent emergences on many rivers on overcast days. All stages of the hatch are important, but on a calm cast day the duns take center stage. Trout from every corner of the river will line up to rhythmically feed. Midges make up one of the bottom rungs of the May trout food pyramid.
In early May, as long as runoff has not commenced, we will target everything and anything that harbors a population of trout. The freestone fish have shrugged off their hibernation-like winter habits and are actively trying to recoup lost body mass. The tailwater fish are in the midst of the great feed. The stillwater trout are gorging and enjoying the recently receded ice.
The Yellowstone River can produce a truly epic hatch of Mother’s Day caddis and baetis can appear in very fishable numbers on cast days. The only issue with the Yellowstone is the lack of a dam. It seems most years that right as the excellent numbers of caddis appear the river huffs and puffs and blows right out. However, the weeks before the appearance of the caddis can be some of the best dates of the year.
The Paradise Valley Spring Creeks provide my favorite fishing venue in the world. Strong hatches of midges and baetis can be found daily. The fish, while wary, can be taken with a proper pattern and presentation. When the fish aren’t rising everything else remains on the table, streamers , mice, and nymphs all play.
The stillwaters in Big Sky country can provide quality fishing for quality trout. As the ice has recently receded the fish have gained solar warmth and are on the prowl for food. While small insect imitations can work, this is the prime season to take fish on stripping leeches. Explosive grabs and trout measured in pounds not inches characterize the stillwater scene.
The Madison River is the centerpiece of May fishing. The Madison provides 31 days of quality trout fishing in May. While symptoms of runoff do present on stretches of the Madison in May there is always fishable water. The waters from Lyons Bridge to Hebgen Lake provide the best opportunities for numbers and the greatest diversity for angling opportunities. Additionally, this stretch is closed to fishing from the boat forcing an intimate angling situation. Some years the river provides solid fishing from Hebgen to Ennis. On Especially wet springs the tributaries will contribute significant color, usually this occurs sporadically. The river below Ennis Lake produces consistent fishing to Cherry Creek without fail. Sporadic pushes of dirty water will temporarily shut down the water that exists below.
Depending on who you consult, many anglers consider May the peak fishing month on the Missouri River. Strong hatches, 50 degree water, thousands of fish per mile, and grass free water provide exceptional fishing. Need I say more?
While many ‘may’ think the month of May is largely characterized by runoff they couldn’t be any further from the truth. Quality fishing in May is a categorical imperative.