As the weather and water gets colder, trout don’t move all that much, and they’re close to the bottom. Focus your efforts on nymphing in deep water, slowly. Just because it’s cold and winter, you don’t have think small, trystoneflies and small streamers.
On cold days, fish are less active in early mornings. Try fishing later mornings & early afternoons, typically 10am - 2pm is great for winter. When the weather is forecasted to be warmer and the sun is out, look for fish to be more active due to rising water temps. On very sunny winter days, trout will move into faster riffles to feed. You may also have luck on a gray, snowy day without wind. During these conditions, hatches could be imminent, and there are memorable days to be had fishing dries while watching the snow fall.
As water temperatures decrease, trout become lethargic, and everything slows down. In effort to overcome changing water temperatures, try fishing tailwaters where temperatures remain more constant. Generally speaking, fish in these waters will continue to feed throughout the day and gives you the angler the best chance for winter success.
Streams are normally low and clear in the winter allowing fish to see your leader and tippet more easily. As such, reduce the size of your tippet. If you usually fish a river with a 5x, try a 6x tippet. Also, when fishing the tiny winter dries try adding length to your leader and present the flies to the fish first.
In the winter, it’s important to slow down. Allow more time between casts, observing fish behavior and reaction. Keep every variable in mind knowing trout are very spooky in the winter, especially if they move to the shallows to feed. When fishing deep slow runs make a lot of drifts, fish lying on the bottom will not necessarily move to your fly, and getting it right in front of their nose is often the trick.
Fly selection is important particularly in the winter. We thought Hatch Magazine had five good flies to get you through the winter – Zebra Midge, Frenchie, Walt’s Worm, Glo-Bug, and Pheasant Tail.
Protect fish and yourself from the cold. Hatch Magazine points out that catch and release practices are especially important in the winter – keep fish in the water while unhooking them, remove gloves and wet your hands before handling fish, and dry your hands with a small microfiber towel to keep them dry and warm.
In the winter, fish are more astute than ever. Step lightly since fish can sense sound and vibration. Avoid wearing bright colors as it's a dead giveaway to trout.