Spring can come late in Montana and often doesn’t last long before summer is in full effect. During this short window many of the rainbow trout leave the river returning to spawning grounds, primarily the Dearborn River and Little Prickly Pear Creek. Fear not however. Many will stay and the brown trout are shaking off the winter cold and out on the prowl. Streamers will fool some nice ones and the opportunity for a little dry fly fishing will also present itself. Early spring is dominated by midges. Days with good hatches will bring rising trout and midge larva patterns will work underneath when you can’t find risers. Toward the end of April, the Blue-Wing Olives (BWO’s) and March Browns start to appear and the fish don’t fail to notice. Cloudy days will trigger hatches that can make it seem as if every fish in river is feeding on top. Nymphing will produce consistent results with midge, baetis, pt’s, and scud (egg?) patterns topping the list. In late spring, the fishing begins to heat up both subsurface and on top as caddis and PMD’s begin to show in force.
Streamer fishing is pretty good this time of year as well (especially in high and dirty water) though it starts to steadily decline as summer approaches. Temps warm at the end of May and start of June causing the snow pack to let go. The river may become off color for a few days at a time, but rarely any longer and is always clear for the first 5 miles or so below the dam.
Spring weather varies from cold and snowy/rainy to warm and sunny. Perhaps more dynamic than any other time of year, spring mandates bringing cold and warm weather gear. Often, you will need both in just a few days time.