After the snowy and cold Colorado winter, March helps us transition to the longer, warmer days ahead. Rainbow, cutthroat, and cutbow trout take advantage of this change and begin to feed in preparation for their upcoming spawn. Typically, more food is available as well, with hatches of midges and blue-winged olive mayflies occurring regularly. The midges are often on the larger size (think 18’s and 16’s) in various shades and trout really put on the feed bag gobbling down these morsels.
What this offers the angler is the chance to catch some of the biggest trout in the system. Flows are typically low and clear and the fish are still holding in or close to their deep winter lies. The river valleys typically warm with the sun even though the higher altitudes are still cool. Looking back at my years chasing trout in Colorado, I’ve had some of my best personal and guiding days in the month of March, with some of the biggest rainbows, cutthroats, and cutbows I’ve seen.
The pre-runoff wading in these low, clear flows is typically as easy as it will get. In addition, fly fishing in March offers another benefit – almost zero crowds. Finally, after months of not seeing angler pressure or artificial offerings, the degree of difficulty is lowered in fooling the hungry trout.
This pre-spawn window of time is indeed magical, and limited, as eventually the trout will engage in their normal spawning rituals. Males will battle and females will make redds. We leave those fish alone to their baby-making bow-chicka-bow-bow times. In conclusion, you need not wait until summer to fly fish – some of the best fishing in year happens in March!