Why Winter: What's Behind the Growth in Cold-Weather Angling?

A decade and a half ago, winters were downtime for me and almost every other guide in the Rocky Mountain West. We worked our butts off from early April until Thanksgiving, and then spent the next four months having lots of fun. Where I live along the Wyoming-Idaho border, it was nothing for me to squeeze in 70-plus days of skiing between December and March. There were also a couple weeks dedicated to steelhead, a saltwater flats trip, or perhaps some surfing. It was financially draining. It was also a hell of a lot of fun.

Things began to change in 2008. On Christmas Eve that year, the shop manager called to see if I was willing to guide a party the next day.

“A guided trip? In winter?” I replied. “They can’t be serious. It’s gonna be 23 degrees tomorrow. Why don’t they want to go skiing like the rest of us?”

But they were serious. I was single at the time, and most of my extended family were gone for the holidays. So, I accepted.

We caught a few fish that afternoon, and my guests seemed thoroughly satisfied. Before packing up for the day, one of them said, “I have been on five ski trips in the past seven years, and I’ve caught fish on every one of them.”

Clearly they knew something I didn’t.

At first, I thought a trip like this was a one off. But another one came in a month later. Two more bookings occurred in February. Another two in March. Since that winter, I have watched the slow but steady, growth of fly fishing during the snow season. By no means is it the level of the rest of the year. Nonetheless, that growth is occurring. In Wyoming and Idaho, single-day license sales between December 1 and March 31 have grown substantially since 2011.

We see it on magazine covers, in films, and through social media posts. Why are more people fishing in the winter? What’s causing this growth?

One reason is that, due to regulation changes, there is more water available now than a couple decades ago. My beloved Henry’s Fork has been open year-round for decades. But nearby waters like Wyoming’s Snake River and the South Fork of the Snake in Idaho were not open to 12 months of fishing until 2004. This trend has been occurring on streams across Montana as well for at least the past dozen years.

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Anglers are also seeking out less congestion. Winter fly fishing is on the upswing, yet its growth is far outpaced by what we are seeing during the prime-time months of May through September. The situation throughout the West has reached such a point that Trout Unlimited’s Kirk Deeter predicted a “season shift” among the army of veteran anglers seeking fewer crowds. Winter offers just that.

But more than anything else, a warming climate is driving the increase. Summer fly fishing is only getting harder for trout with each passing year. The historic droughts in 2021 and 2022 led to full or partial closures on streams across western Montana due to high temperatures and low flows. Even tailwaters weren’t spared. Management agencies in other states issued recommendations to end fishing at specific times of the day, often called “hoot owl” restrictions. Fishing was not permitted on some watersheds between the hours of 2 P.M. and midnight. This resulted in even more congestion on less-impacted, higher-elevation streams that didn’t have closures.

Anglers I guided that summer were rightly concerned about inadvertently killing the trout they hooked. I assured them that precautions would be taken, including bringing our flies in for the day when water temperatures hit 68 degrees F. Most of the waters I fish have been going over 68 degrees for at least a couple weeks at a time since 2012. Some of my longtime guests are abandoning August altogether in favor of cooler months. I encourage such moves.

Water temperatures in winter, on the other hand, remain predictably cool while the air we’re fishing in seems more tolerable and comfortable for us. I’ve yet to measure water temperatures over 45 degrees between December and March on the streams I fish regularly. At the same time, the air temperatures often exceed the 45-degree mark.

Low & Cold

Winter fly fishing is intimidating for the uninitiated. Many people are unsure how to fish streams that have so radically changed from summer. I understand the apprehension. However, gaining knowledge about winter riparian environments—including the impacts on trout behavior and food sources—breaks through the unease we create in our own minds.

Most Western rivers are often at their lowest flows of the year from December through March. The dams feeding many rivers hold back water for later in the year. Freestone streams also experience reduced flows due to natural processes. It snows rather than rains, and the resulting snowpack will not melt and create runoff until spring. All of this leads to reduced flows and reduced habitat on streams. Riffles, seams, and bankside troughs that were teeming with trout a few months before become high and dry. Add to this the fact that water temperatures are cold. The body temperatures of trout are going to be close to that of the water. Even moderate current speeds are difficult for trout to hold in, let alone feed. These two conditions coalesce to the benefit of fly fishers. While habitat has changed, fish populations haven’t. That means these same fish concentrate in the precious holding water that still has sufficient depth (which provides protection and slightly warmer temperatures) and slow current speeds. Pods of fish congregate in these areas.

This is a prime advantage of winter fly fishing—a single pool will likely contain several, if not several dozen, more trout than it does the rest of the year. Winter holding water with sufficient depth and current speed include eddies, backwater side channels with seams along main channel currents, ledgerock pools, and the middle and tail portions of riffle pools.

A large concentration of trout does not necessarily mean easy pickings. With cold water temperatures comes slower metabolism. Trout do not require the same amount of nutrients as they do the rest of the year. I have found on days when water temperatures are 36 degrees or lower, there is very limited movement by trout to forage. You must get your offering right in their face for them to eat. Above 36 degrees, however, I observe noticeably more movement. When water temps are 40 degrees and over, movement and feeding are even more pronounced.

A common belief held by many fly fishers is that warming air temperature contributes to warmer water during the winter. If this is the case, starting your day at 1 P.M. would be a sensible choice. This advice has been repeated in books and magazines for many decades.

However, my experience is that warming air temperature melts ice and snow on surrounding banks. This process can, at times, lead to a cooling of river water. I have observed midafternoon water temperatures that were two degrees cooler than at 10 A.M. The air temperature was rising, but the water temperatures were dropping. Trout and bug activity changes in very narrow temperature windows, and while it’s true that warmer water can spur feeding, the temperature might not always be headed in the direction you think.

Does It Harm Trout?

Some anglers feel it’s wrong to target trout in harsh winter conditions—especially after hounding them for months on end. They sometimes argue that fishing in such cold water is borderline lethal for trout. Don’t they deserve a break?

Such a viewpoint is silly and uneducated. These same fly fishers are probably the ones pounding the water on a 90-degree August afternoon when conditions are truly dangerous. Perhaps their real issue is a lack of perseverance when the weather gets a little chilly.

The fact of the matter is that cold water contains significantly higher concentrations of dissolved oxygen than the warmer water we experience later in the year. Trout depend on dissolved oxygen more than almost any factor. The fish we hook, fight, land, and release in winter have a far greater chance of survival. This is one of the reasons states like Idaho and Wyoming made the decision to open a number of streams to 12 months of fishing.

I am confident winter fishing is safer than other times of the year. Nonetheless, we still need to take precautions.

Consider the fact that a trout’s body temperature is close to that of the water they live in. If a river is 37 degrees, most likely their bodies are close to the same. Handling trout with substantially warmer hands not only strips their bodies of their protective slime layer, it burns them.

It is critical to submerge your hands both to wet them and to cool them down. It’s uncomfortable for you but far less so than a branding iron, which is what a warm, dry hand could feel like to trout.

An important safeguard used by many anglers when handling fish is to minimize their exposure out of water. This ensures that gills remain saturated with oxygen. I typically give it a five count—after five seconds of exposure, the fish must be submerged.

Exposing gills to cold air can freeze the delicate filaments that process and exchange oxygen from the water. The sclera—a protective outer layer covering the eye—is also prone to freezing. These are both good reasons to take the same precautions in winter as we do the rest of the year.

More than Just Midges

Ask 100 fly fishers what trout foods they associate with winter. Most likely all will say chironomids, and for good reason. Midges always seem to be around. They make up one of the largest forms of biomass on most trout streams. I rely heavily on chironomid imitations on most winter days whether I am guiding or fishing for fun. Many times, midges are the only game in town. When you see fish feeding on the surface, there’s a good chance they are eating midges.

Yet many other forms of forage are available to trout during the winter. And at certain times, they can match or beat midge imitations.

A continuously overlooked winter trout food imitation is egg patterns. Mountain whitefish are native to western North America and still populate many streams in strong numbers. Their spawning activity occurs late in the year—generally from mid-October until mid-December—and takes place in main channel currents.

Female whitefish do not build protective redds like most trout. Rather, they deposit roe directly onto the riverbed. These eggs are readily available to trout waiting downstream. This timing and spawning behavior make egg patterns a good choice for fishing riffle pools and seams during December.

The cold months of January and February often result in habitat reduction on small tributary streams due to continually declining flows and iced-over water. This produces a surge of baitfish and juvenile trout in the comparatively more hospitable environs of downstream rivers. These fish seek out the same slow backwater channels and eddies as trout. They are both food and intruders. Baitfish can get hammered if they trespass the feeding lines used by more dominant trout. Sometimes trout won’t budge for a tiny midge, but will inhale a small streamer.

Little Black (Capnia) and Little Brown (Nemoura) stoneflies are collectively known as tiny winter stones. Other than the ever-present midges, they are among the first emergences of the year on many Western streams, with hatches occurring from early February until mid-April. There are two key times when tiny winter stones are available to trout: 1) when the nymphs move en masse to shorelines to emerge from their shucks, and 2) when female adults return to the surface to lay their eggs (often while in a mad, wake-producing scurry). Tiny winter stones are generally in the #16 to #18 range. Patterns like the black Perdigon or Furimsky’s BDE are among my favorite imitations.

I turn to roe patterns, winter stone imitations, and streamers when the time is right. Sometimes I do it simply because I get bored of fishing midges. Keep in mind, however, that the nymphal and larval forms of other invertebrates are still around. I have caught fish on giant Pat’s Rubber Legs, soft-hackles, blue Copper Johns, cranefly larva patterns, and even San Juan Worms, during the winter. So don’t get too caught up in matching specific forage. The water you are targeting will be far more important than the flies.

Staying Out There

Winters are getting warmer. But they are still colder than the rest of the year. This can always limit your success. It impacts your equipment and your comfort level. Going in prepared to deal with the elements will make your time more enjoyable and keep you out there longer.

Top-of-the-line waders and apparel will keep every part of your body warm and dry except your hands. Fingerless gloves—a winter fly-fishing requirement—still allow your digits to go uncomfortably numb.

One game-changing remedy is black nitrile surgical gloves. Worn under fingerless gloves, they are thin and skin tight. Nitrile gloves allow you to feel and manage line, select tiny flies from your boxes, and tie knots. At the same time, they repel wind and water and absorb sunlight. Under certain conditions, they almost render your hands too warm. Some proponents also claim trout can be handled with less harm with nitrile gloves. When wet, they feel slicker than wet hands. Both these traits limit potential damage when compared to a warm, dry hand or slime-stealing fleece gloves.

The waders you wear in the summer might not be appropriate for winter. If they don’t allow for adequate layering underneath, you can get chilled to the bone. You need room in there for layers and still to be mobile enough to stay safe.

Chilly conditions can impact your gear as much as your body. Nowhere is this more evident than with ice buildup on rod guides. It limits your ability to cast and manage line. When it’s severe, the only fix is to stop fishing and break it out as best you can. Doing so risks damaging your rod.

A whole slew of deicing agents have been employed over the years to prevent ice buildup, including Ice Off Paste, black label Chapstick, and the useful, although incredible messy, Pam cooking spray.

It was only a couple years ago that Grant Michaels introduced fly fishers to the qualities of Lemon Pledge as the cleanest and most effective deicing substance. I have become a convert. Its ingredients—including isoparaffin and silicone—work synergistically, allowing water to bead up and drop off the rod and guides. I would not call this a cure-all. However, I get more ice-free casts with Lemon Pledge than I do with other agents.

Much of my dry-fly fishing in the winter relies on midge and tiny stonefly imitations. I use CDC as wing material for most of my patterns. It’s imitative, visible, and floats like a cork when presented properly. Yet when it does collapse after hooking up on a fish, it can be difficult to dry by simply casting it in the cold air. Hydrophobic materials like desiccant work well on most fly materials. This is not the case with CDC.

I use Bounty paper towels as a drying agent. Super absorbent, Bounty literally sucks the water out of the fly without the crystals and white residue in the material that desiccant leaves behind. Its so effective, I use it all year, but it becomes especially important in the winter.

Winter Is Coming

The growth of fly fishing over the past decade is a four-season phenomenon impacting more than just trout streams. Steelhead rivers, saltwater flats, and bass lakes are feeling it too. It’s great witnessing the joy folks get from adopting the sport. But the summer crowds can be maddening, and much of the congestion on trout water is happening at a potentially harmful time of the year as stream temperatures get warm.

Winter is a respite for both trout and anglers. The crowds are not there, and more importantly, trout have heavily oxygenated water that allows them to recover quickly after they are released. If we treat them with the precautions I mentioned above, mortality will remain low. Winter is coming. So embrace it. Fish it. And enjoy!

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Boots Allen is a fly-fishing guide and writer who lives with his wife and two kids in Victor, Idaho. His latest book is Finding Trout in All Conditions (WestWinds Press, 2016).