Gallatin River Fishing in May

May Fly Fishing on the Gallatin River

In May, the Gallatin River gradually goes from spring thaw to peak runoff. Snowmelt swells the river and degrades clarity. Fishing can be good during the earlier weeks of the month, but there's a countdown to June when the river becomes inhospitable for a few weeks.

Trout feed aggressively near banks and mid-river structures, but wading gets harder due to rising flows.

Gallatin River May Hatches

Blue-winged olives, March Browns, and Midges hatch with frequency in early May. Caddis become increasingly active in the Gallatin Valley sections and can provide some terrific dry fly fishing in the evenings when water levels are stable.

Bozeman Fly Fishing Guide Pro-Tip:

The river can be dirty this time of year but there are still good angling opportunities if you go North above the Taylor's Fork Creek near Big Sky, MT. The Gallatin River is normally clearer above this creek as it is the main source of sedimentary runoff. We like to nymph a Brown Pat's Rubberlegs #10 and a Red Sparkle Worm #10 along the banks.

Gallatin River Fly Fishing Techniques for May

Anglers wade carefully amid rising Gallatin River currents, intercepting trout targeting protein-rich foods. Short casts, tight to structure with weighted nymph rigs find some large Brown Trout as water levels rise and clarity starts to diminish.

Switch to heavy sink tips and dredge streamers through holding lies as the river rises.

Dry fly-fishing opportunities abound in the early part of May, so long as water levels and clarity remain stable.

Our Gallatin River Fly Box for May