When the air temperature drops into the low 40’s and 30’s and the occasional snowflake brushes against your cheek, you know things will be different the next time you go fishing. The hum of wings and chaotic flight of insects on a warm summer’s evening are long gone. It’s rare now to see any insects flying about, and one would assume that aquatic insects are as few and far between on a cold winter’s day as their terrestrial cousins. Interestingly enough, however, this is not the case. The winter months will find the insect life in streams and lakes rich, abundant, and active. In fact, the abundance of aquatic insect nymphs and larvae is typically greater during the winter than during the summer and late fall. This is a reflection of the emergence patterns for many aquatic insect species; mature nymphs and pupae emerge into adults throughout the spring, summer, and fall. As a result the stream is left with low numbers of nymphs and larvae. The adults return to the water within days or weeks to lay eggs, and those eggs often don’t begin to hatch until early to mid fall. By the time winter rolls around a whole new generation of insect larvae are scrambling among stream-bottom rocks actively feeding and growing even as water temperatures approach freezing.

While most of the action in the winter is underwater, there are a few species that emerge to adults through the winter. These hatches may not be as dense as those of warmer months, but they can still create surface feeding activity from trout that have few options when it comes to surface food during the winter. Since terrestrial insects are virtually non-existent during the winter, trout must rely on aquatic species for food, primarily on the underwater stages, but also on those adults that take to the air on cold winter days.

A winter’s day of fishing has it’s own rhythm of activity unique to the conditions of the season. Understanding those rhythms can help you decipher when, where and with what to fish. With that in mind let’s take a look at what might be considered a “typical” winter’s day of insect and fish activity.

Morning

There are few winter mornings that find me standing knee deep in ice-water fishing. However, that’s not because fish can’t be caught. It has more to do with my comfort to catch quotient, which has moved more to the comfort end of the scale as I have grown older. “Been there, done that” comes to mind as I contemplate frozen fingers and ice clogged guides. But that’s just me. As my Uncle use to say, “You can’t catch any fish unless you fly’s in the water.” Of course that was usually in response to the many branches and trees my flies kept hanging from when he was teaching me to fly fish.

Mornings present the coldest water and air temperatures of the day. Since insects and fish are both cold blooded – essentially the same temperature as the water they live in – winter mornings are not a hotbed of activity. But even a small increase in temperature from the warming rays of the sun may start some fish moving and feeding. Their primary food will be whatever nymphs and larvae are available on the streambed and drifting in the currents. To determine what that might be take a few minutes and collect a sample or two of insects from the stream bottom using a sampling net. Look for the most abundant and active nymph wriggling in your net. That will be a good choice for a nymph pattern fished along the bottom. If by chance you find some of the insects are mature and look ready to emerge, then you might find a nymph fished closer to surface will work well. Because the winter population of insects is routinely quite diverse, it can take a little time to sort out just what fish might be feeding on. Just because it is winter doesn’t mean trout will be completely unselective in their choice of food.

Nymph fishing on a winter morning will certainly hone your skills for nymph fishing other times of the year. The sluggish metabolism of winter fish means their takes are softer and subtler than ever. It also means they won’t go as far out of their way to take your fly. Thus reading the water and being able to detect the softest takes is critical if you hope to hook some winter trout. I find a strike indicator essential for such nymph fishing. I also find that casting as short a line as possible to effectively fish a piece of water improves my odds of detecting a strike and setting the hook quickly – seems fish can spit out a nymph just as fast in the winter as in the summer. Also keep moving and fish new water. Since many fish won’t be actively feeding you need to cover as many fish as possible to increase your odds of finding one ready to take a fly.

Later Morning – Early Afternoon

From about 11:00 to 3:00 is when I want to be on the water in the winter. By 11:00 air and water temperatures have risen, fish are more active, and if any insects are going to hatch they will usually start between 11:00 and 1:00. Because so few insects emerge in the winter, there will usually be just one dominant species on the water. In the winter you won’t have a difficult time deciding what to imitate when a hatch occurs.

What hatches are you likely to run into during the winter? I find there are three hatches that consistently show up when the weather turns cold: chironomids, winter stoneflies, and Baetis or blue-winged olives. There are literally hundreds of species of chironomids in streams throughout the country. Many species seem to emerge only in the winter. Because there are so many species, it is important to collect some of the naturals floating downstream to determine their size and color. Just as in any other season the pupal stage, drifting slowly up to the surface, is often the most effective stage to imitate. Due to the cold water pupae will hang in the surface even longer than normal before the adults emerge, so fishing a midge pupa in the surface film can be very effective. The cold conditions also result in more stillborn adults – adults that don’t escape completely from the pupal shuck and end up dead or dying in the surface film. As a result dry patterns that imitate a struggling or dead adult can work quite well.

Winter stoneflies (primarily of the family Capniidae and Nemouridae) are small (size 18 to 14) dark brown to black stoneflies that emerge primarily in the winter. I commonly see them during winter cross country skiing trips that take me along a mountain stream. The dark colored adults look like ants running over the snow along the water’s edge. The females of many species of winter stoneflies are wingless, which only adds to their ant-like appearance. After mating on the bank the females crawl or fly back to the water to lay their eggs. Most end up caught in the water’s surface floating downstream. Small dry flies that match them in size and color will often take some nice winter trout.

Baetis, or blue-winged olive, hatches can be a real treat in the winter. Depending on where you live good hatches may occur anytime between November and March. Some winter days will produce hatches just as heavy as on a good spring or fall afternoon. Small nymph patterns work well before the adults start popping up to the surface. As adult activity increases switch to small emerger patterns and of course dry flies will work too. Even when there is good surface feeding activity the fish are still more sluggish than normal so presentation is critical – drift your fly right down a trout’s feeding lane without any drag. Also check the size and color of the naturals carefully. These will vary from stream to stream, and even week to week.

Late Afternoon – Evening

The sun drops below the horizon early in the winter, and when its rays disappear the warmth they provided quickly disappears as well. In my experience this often results in a surprisingly quick end to both insect and fish activity for the day. Spinner falls or other egg laying activity will not wait for the soft light of evening in the winter. If they haven’t occurred by late afternoon they probably won’t occur until the next day. Likewise fish seem to suddenly stop feeding when the day’s light fades. Switching back to some deep fished nymphs may pick-up another fish or two, but I am usually ready to watch the sun set and notice how quiet and peaceful a stream can be in the winter. You can sometimes extend the time period of good fishing by half an hour or so by finding a stretch of stream where the sun is not yet blocked off the water. Make note of the areas on the streams you fish where the sun’s rays linger the longest. They will be the perfect place to end a winter’s day on the stream.

Final Notes

First, clear winter days have very low humidity. This is not good for tiny adult insects that struggle to prevent dehydration. This can result in the interesting winter phenomenon I call the “snowstorm effect.” If you fish much during the winter you will find that some of the best hatches occur on wet overcast days, especially it seems when there is a good snowfall. My theory is that these days provide the humidity needed to protect the hatching adults, and somehow the nymphs underwater can recognize those conditions. Therefore, don’t wait for a nice sunny day to spend some time on the water. An overcast snowy day may be just the right conditions for some hot fishing on a cold day.

Second, hatch activity in the winter, when it occurs, will often be compressed into a short period – an hour for example. This means you will need to be in the right place at the right time with the right flies to take advantage of the brief opportunity. Being the first angler on the water doesn’t matter in the winter, but you don’t want to be eating lunch during the only hour of good hatch activity. Keep this in mind as you plan your day.

Third, spend some time looking in the stream for what insects are there for fish to eat. Many anglers assume that fish aren’t selective during the winter and any old buggy looking fly will work. However, as I mentioned earlier, the diversity and abundance of insects peak in the winter, so it is important to select a fly pattern that matches the dominant insect. Match its size and shape and fish it in the best fish holding water.

Finally, with some rare exceptions, a good day of fishing in the winter will not equal a good day during other seasons. Therefore, don’t expect to see lots of rising fish or have them chasing your flies across the water. Successful winter fishing requires patience, good reading water skills, careful observation, and good casting and presentation technique. If you can find and catch fish in the winter, you’ll really shine when things warm up in the spring.