Winter is upon us and it is time to consider what this means for fly fishing in Colorado. At FlyCast, our goal is to provide you with the most up-to-date and forward-looking fly fishing information for a growing list of Colorado rivers and streams. In general, our focus has been on the short-term (looking ahead to the next 7 days). However, we would be doing you a disservice not to consider the long-term implications of winter weather on fly fishing conditions in Colorado. In our inaugural long-term “Winter FlyCast,” we will properly equip you with the information and know-how for a successful winter fly fishing season.
Weather forecasters are working tirelessly to make long-term predictions around ambient temperatures and precipitation across the U.S. this winter. In the case of long-term weather forecasting, the old adage “nothing is certain but death and taxes,” could not ring more true; meteorologists will be the first to admit it. Nonetheless, we can utilize the data at hand and the lessons learned from winters past to prepare ourselves for anything and everything Mother Nature might throw at us.
There are a number of sources that provide long-term weather outlooks such as The Farmers’ Almanac and Old Farmer’s Almanac, but none are more forthcoming when it comes to transparency and methodology than the National Oceanic Atmospheric Administration (NOAA). As such, we will reference NOAA’s winter forecast for the purposes of this analysis. NOAA is calling for a mild winter in much of the United States with above average temperatures across the northern and western states. Additionally, there is a 70 to 75 percent chance of an El Nino year, meaning a higher average of precipitation in the South and drier conditions in parts of the North are likely to occur. You’re probably thinking, get to the point…what does this mean for Colorado?
Winter Fly Fishing in Colorado
Colorado is unique in that NOAA is forecasting warmer than average temperatures and a wetter than normal winter. This is great news from a fly fishing standpoint. Comparatively, warm temperatures mean trout will be more active and for longer periods of the day and season. Additionally, bug life – particularly of the midge, BWO and, to a lesser extent, the stonefly variety – will be more prevalent, having trout feeding at higher rates. Anglers in Colorado are notorious for their early mornings on the water due to the crowds and limited river access. We’re here to tell you to sleep in, but not too late! During the winter, trout are generally less active in the early hours of the day and are more focused on conserving energy; as air and water temperatures rise, they will begin to feed more heavily. For a colder than normal winter, we’d say get to the water after 11 am. However, with a warmer than normal winter, you should shoot for 10 am and look for productivity to improve throughout the afternoon.
Winter Fly Fishing Tactics
Now, let’s talk tactics. Given that trout are generally sluggish in the cold, they will predominantly hold in the calm, deep pools and runs, feeding along the bottom of the riverbed where the current is the slowest. This allows them to expend the least amount of energy while garnering the most nutrients. This means nymphing will be the name of the game and in order to reach the deepest water columns, we highly encourage you to use ample weight. With that being said, assuming a warmer than normal winter, trout are more likely to venture out into the more shallow, faster moving riffles and seams during peak heat hours (1 pm to 3 pm). In this case, you’d want to switch out to a lighter rig and utilize emerger patterns. If you’re lucky, you could stumble upon a midge or BWO hatch. In which case, break out those dries! For many of our forecasted rivers, particularly tailwaters, we always encourage smaller flies. This is especially important in the winter. In fact, go even smaller! Trout will be more inclined to feed on those micro (#22 - 26) midge and beatis patterns as they better reflect what’s actually floating in the water.
From a precipitation standpoint, a wetter than normal winter means higher run off in the spring and a lower chance of drought in the summer, which is great from a conservation standpoint. In the winter, however, it means highly variable fly fishing conditions, specifically around trout feeding behavior. Storm activity and precipitation go hand-in-hand, which means you’ll want to pay extra attention to the weather forecast and our daily and weekly FlyCasts, as timing is everything in this environment. While it might sound counter intuitive, the least productive day you could choose to fish is a sunny day following several days of storms. On days like this, air temperatures are likely to be colder, despite the sun, the wind will howl, the river will be a slushy mess and the trout will not be inclined to feed at a substantial rate. Conversely, look to fish the days leading up to a storm, especially days with cloud cover. The cloud cover will prevent large temperature swings and sock in the heat keeping overnight temps at bay and lead to a warmer subsequent day. Trout are not the only species that are more active on warmer days. Warmer air and water temperatures will encourage aquatic insect life activity, resulting in higher feeding rates. Finally, flat light provides trout a sense of protection from aerial predators, as they are more sensitive to changes in light intensity, giving them an advantage over birds of prey. As a result, trout will move about the water more willingly and feed more confidently. Flat light, comparatively warm air temperatures, and increased aquatic insect activity will lead to fishing that is more productive.
While weather forecasts are subject to change, there are a number of reasons to get excited about fishing this winter. You can expect fewer crowds and get a later start, as productivity will be slow in the morning with freezing air temperatures and sluggish trout. A warmer than normal winter forecast means trout will feed more actively and you can plan on longer windows of productivity. Shoot to start by 10 am to 11 am and finish by 4 pm. A wetter than normal winter will lead to consistent storm activity, making for highly productive fishing on days leading up to the storm, and the cloud cover will incentivize trout to feed more heavily.
As always, stay tuned for updates as weather forecasts will inevitably change, and keep an eye on our daily and weekly FlyCasts for the most up-to-date Colorado fly fishing conditions!