It is possible for winter to be the most rewarding season of the year for the fly angler, if they can stand the cold, that is.
On the positive, you very well could have the river all to yourself, enjoying seclusion that is seldom found whenever the mayflies are hatching in the spring and summer.
But there is one more reason to get out and fish between in the winter: that time between December and March can also be the most difficult time of year, requiring accuracy and skill, more so than any other time of year.
Basically, if you can catch fish in the winter, you can catch them any time.
The strategy to catch fish with flies in winter can basically be narrowed to four simple rules:
Slow Down; Size Down; Tone Down; Present Down(stream).
So, here is the lowdown.
#1—The Trout Forecast: Whenever water temperatures fall, the trout themselves also slow down. Their metabolisms significantly lessen, they're increasingly lethargic. They never run after flies as purposefully in winter as they would when the temperature of the water is in the ideal trout zone of forty-five to sixty-five degrees. One way to bypass that, naturally, is to fish in tailwaters—rivers that run from bottom-release dams. The water put out from these dams generally remain at a constant temperature in the forties or fifties all year long. As a result of this, the fish do not really feel all that much difference between July and January, though one should note that diminished days and seasonally distinctive insect hatches do change the fishing paradigms significantly between summer and winter.
#2—Stalk Softly & Cast High: When trout are slowed down for winter, the smart fisherman will slow down too. Rivers are generally at their lowest and clearest in the middle of winter. Vibrantly white, snow-coated banks mirror light and magnify shadows much more. While winter trout are not as jumpy as in the summer months, that does not mean that they're significantly less spooky. It is recommended that you slow down your pace and movements by no less then twenty-five percent when fishing in the winter. An area of particular concern is the position of the lower winter sun, so be careful not to cast long shadows over the runs you target. You may also consider spending more time high on the riverbanks spotting fish before you cast. If you can see and then specially target trout, your odds of hooking up are tremendously higher than when you try blind casting during the cold months.
#3—Make Slow & Short Strips: Streamer fishing can be effective in winter, particularly in tailwaters. Then again, you will probably tend to slow the tempo down a notch in winter. Instead of the long, aggressive strips you might make with your fly line in summer or fall, you should be more likely to make slow, choppy strips in the winter season.
#1—Be a Nymphing Maniac: You should fish with smaller flies in the winter, and basically all of winter flyfishing is nymph fishing. At any point during the year, midges make up over half of a trout’s diet. So these tiny bugs are incredibly important for fishermen to comprehend and replicate all year. But the midge game is specifically essential in wintertime, since there is very little mayfly and terrestrial activity at that time.
#2—Black Stoneflies Are Best: Another bug that you should cash into during the winter is the little black stonefly. Although these stoneflies share the same fundamental shapes and darker colors as their summer and spring equivalents, these bugs are usually a lot smaller (size 16 or smaller). Although small egg flies and attractors like Prince Nymphs are useful winter patterns, an angler won't have to worry in most locales if they choose to fish little black stoneflies and small midge patterns such as zebra midges, juju midges, and black beauties.
#3—Lighten Your Tippet: Make a point to size down on your fly rig when you trout fish in the winter. If fishing a river with 4X tippet, drop down to 5X. The light and shadow contrast on bright winter days add to the low clear water to create a recipe for making trout more leader shy than they might usually be in summertime. It is also important to drift flies straight to the trout in winter, so smaller tippet aids in presentation.
#4—Same With Your Strike Indicator: Don't throw big, gaudy strike indicators in the winter. Instead, make use of small pieces of yarn, pinch-on foam, or if the water is really low and slow, use a dry fly like as small parachute Adams as a de-facto strike indicator.
#1—Be Dull (really): Generally speaking, winter requires more duller, darker colors than any other season. This applies to everything - from the flies you fish with, to the colors you wear on your body. Generally, small black flies are the best kind to use in winter. Tans, browns, and greens also work pretty well. Steer away from the bright accents you might find like sparkly wing cases and shiny beads as much as you possibly can. Black or glass beads generally work much better when you're wanting to use a weighted fly. And though you shouldn't be scared to fish in a loud Hawaiian shirt in the spring and summer (excluding any repercussions in the fashion world), in winter you might consider wearing white, black, tan, or sky blue. On a snowy riverbank, even just a red baseball cap will be a dead giveaway to the trout, and it'll negatively influence your fishing.
#2 - Wait Longer In Between Casts: Another important factor when it comes to the Tone Down rule involves your casting tempo. You can't be flogging the water during the winter. Wait at least twenty-five percent longer between each cast, and take time to watch the fish react to those casts, whether or not they actually eat the fly. A trout’s body language can reveal when you should cast more clearly in winter compared to other seasons.
#1 - Cast Down: Although the vast majority of people prefer to fish from downstream to upstream, in winter you should consider making most of your presentations - including nymph presentations - in a generally downstream direction. When you see a trout holding in a run, you should first factor where the sun is relative to your position, and get yourself in a spot where you can see the fish (without having to worry about excessive surface glare) without creating any shadows. Drop the flies a couple feet upstream of the target fish and let them drift into the zone. Strikes have the potential to be remarkably subtle in the wintertime, so set the hook (gently) on even the smallest stall, stagger, or hiccup in your indicator or line.
#2 - Keep A Close Eye On Your Weight: One other important thing to keep in mind when flyfishing for trout in the wintertime is those fatigued fish are likely to move less to consume a fly. To force them to eat, you basically need to hit them in the head. If you do that, they will eat the flies. The biggest factor in making a good presentation is the weight. Change your weight no less then five times before you even consider altering your fly pattern. You need the bugs suspended so that they float precisely into the feeding lane. That could call for tinkering with your weight from run to run. It also means making lots of casts to produce a bite. So above all else be patient, and pause between every repeat cast.