Winter isn’t most fly anglers favorite season to fish because most anglers just don’t like cold weather. There are exceptions. Those stream which get too warm for trout to live in and are stocked with trout from a hatchery, can attract good numbers of fly anglers. Fly-fishing for stocked trout leave a lot to be desired. That’s fairly common knowledge but most anglers don’t realize that fly fishing for wild trout can be very good during the winter months.
Sure, the cold weather can provide a lot of discomfort. Fly fishing isn’t going to be much of a fun thing to do on very cold, windy days. So, if that is the case, simple don’t go if such forces are against you. However, if it’s been sunny and above freezing for a few days, I’d much rather be fishing than working. Staying warm on cold days shouldn’t be a problem. Wear a base layer and fleece pants beneath your waders. A good base and mid layer, warn underneath a good jacket; maybe warm gloves without fingers and a warm cap or hat can make you feel comfortable in cold weather. Fly fishing can be tough if it is below freezing. If you fish during those low temperatures, ice will accumulate in rod guides unless you put some de-icing paste on your guides.
Fish are cold blooded and that means their blood is about the same temperature as the water. The low metabolism doesn’t permit them to expend much energy, not even enough to be actively searching much water looking for food. Rather they stay in slow moving water where food can come to them rather than them having to spend a lot of energy looking for food. The deepest holes with the slowest moving water tends to make for the best wintertime habitat for trout. Fish will accumulate in these areas because the easy, consistent current allows them to expend minimal energy to acquire the food they need to survive.
Depending on the type of water, trout may have to cover some water to feed. Tail-outs and riffles close to deep runs can provide the food they need to survive. It is always a good idea to cover the adjacent water to deeper, slow moving water.
There are many areas of the nation that doesn’t have to worry about their rivers freezing over. They stay warm enough to fish year-round. Tailwaters offer the most consistent, above-freezing water temperatures. So does spring creeks and other types of spring fed water that stay above a freezing level.