The ideal weather day for most fly fishers means blue skies, a slight breeze, and excellent fly fishing.
Usually, when the wind turns chilly and those rolling grey clouds start to appear, the pressure drops, and most of us call it a day and start heading home.
But if the storm is manageable and doesn’t pose too many threats such as lightning or a heavier downpour, it could be very beneficial to fish through the rapid change and reap the rewards.
Fly fishing in the rain-before, during, and after
So how does barometric pressure affect fishing? Barometric pressure changes along with heavy rain can have a drastic effect on your fly fishing day. If it’s a heavy downpour and the river is washed out, then, of course, your day is unfortunately over, but if it’s light rain periods, this could very well bring an increase in the trout bite.
But sometimes, the bad weather plays an important role in the feeding habits of trout, and this is why most avid anglers choose to wait it out or fish through the low pressure, the cold front of rain. These information are also helpful when you go on fly fishing high water.
Before the rain
When a storm approaches, two key changes are thought to influence normal fish behavior in fly fishing. Rain written weather conditions bring low light and a drop in barometric pressure.
Low light– There is no argument that low light conditions are favored in most fishing circles, especially in trout fishing. It’s one of the most effective techniques on how to fly fish for trout. Trout streams come alive with hatches and trout actively feeding at the first sign of the disappearing sun and inclement weather. Low light conditions are much more favored than sunny days because the predatory fish have more cover to hunt and feed before the watercolor and clarity decreases.
The lower light conditions will also cause numerous hatches to start, and this is the time to fly fishing dry flies for trout. When the hatch starts, it’s a feeding frenzy, and normal techniques with a dry fly will get fish to the net.
Many anglers will catch more fish using larger dry flies in these conditions and continue their ongoing dry fly fishing session until the light rain starts. Trout fishing with larger dry flies in these conditions is very successful and can be very rewarding. If you arent that savvy with the dry but still want to capitalize on the dry fly activity, fishing nymphs can be just as effective.
A double nymph rig fished in the upper water column below the foam lines is a great technique. The fly choice for this can be anything from san juan worm patterns to a glass beaded PTN. Here are some tips on how to tie a double nymph rig.
Barometric pressure- There are two schools of thought when it comes to barometric pressure. The first idea is that when a storm is incoming, the drop in barometric pressure will cause a drastic change in fish feeding. The idea is that all baitfish and aquatic insects sense the same shift in pressure and move closer to the surface to feed or hatch.
The predatory fish sense this and go on the feed. The second idea is that the fish realize the change in pressure results in worsening conditions and decreases the food sources resulting in them feeding hard to stock up.
Whichever you choose to believe, or you may have your own theory, it definitely plays a role in the activity of fish before the rain picks up.
During the rain
Focusing on dries in the slow-moving water before the storm requires you to change your approach for fishing in the hard rain. In heavy downfall rain conditions, the steady rain provides plenty of food for the trout from all the insects being washed off the branches. A large terrestrial fly could work very well in these conditions as hungry trout hold on the edges of the banks sipping anything that passes.
If the moderate rain turns heavier and the raindrops get bigger, the water will start to stain a muddy brown, killing any chance of dry fly or nymph fly fishing. The best choice here is to swing a large noticeable streamer through any fishy-looking lies or holes.
After the rain
If you were brave enough to push through the heavy rains, then you should be in for a treat. Fishing immediately after a storm can produce some memorable catches. The hatches after the rains are usually big and long-lasting, which means heavy feeding trout.
Be ready to switch back to your dry rig, or if the water is still a little dirty, your nymph rig. Many anglers most favor the time on the river when the weather has cleared.
Gear needed for fly fishing in the rain
The fishing gear needed to fish in the rain isn’t any different from when fishing on those lovely summer days. Use the same tackle you would on a blue sky day, a little rainy day, or a day full of rain from a tackle perspective.
The main difference is what you wear. If you are fishing in waders, then you will remain dry and comfy, but if you are using wet flies for trout and wet wading, a quick dash to the car to grab your waders wouldn’t be a bad idea if this is possible, of course. The main thing to have is a warm, waterproof jacket that will keep you dry and cozy throughout the downpour.
Most jackets are very lightweight and roll up to basically the same size as a 1L water bottle, making them very easy to carry in your day pack without any issues.
It’s also a good idea to take a warm, dry change of clothes with you in the van. It’s always nice to change into something dry after a wet day out on the river.
Flies used fly fishing in the rain.
The flies used before, during, and after the rain are important and can make or break your day. Approaching a trip, make sure you have a general understanding of the aquatics of the area, nothing too specific but knowing if there are usually large caddis hatches or if the fish love a hopper will help you have a better understanding of what to fish on your trip.
Before the rain, the hatches will start, and a dry rig in the slower water should do the trick. Your parachute adams or CDC caddis imitations will work here. If the fish stop rising, change to a larger dry #12 Stimulator or nymph rig.
The nymphs can be #12-#16 PTNs, copper johns fly, or GRHEs, anything that will imitate a natural nymph. Finding the water column where there is more food is key.
During the rain, larger terrestrials such as hoppers and spider patterns work well, and if the water starts to wash out and turn muddy, then streamers can be used. Woolly Buggers or Minkys in black and browns with a chartreuse bead should suffice.
Safety concerns when fly fishing in the rain.
A heavy rain storm can drastically change the river conditions extremely quickly. It’s important to know your limits and not attempt anything to put yourself or any fellow anglers at risk. Heavy rain clouds the water, making it difficult to see when wet wading, but it can also raise the water level quickly.
Make sure you know the water you are fishing and how quickly it gets affected by heavy rains. Some waters don’t change much, but others can rise in minutes and turn a perfectly safe trip into a nightmare.
To sum it all up, some of the best fishing weather is pre, during, and post a rainstorm. With a few extra rain tips, a little rain and cooler water can make for magical fishing. Your fly choice is important on these rainy days, and you can drastically improve your chances with a few known fly patterns.
Not all rain is cold rain, and it’s always worth waiting until the storm passes to see what the fish will do. So next time you are heading out for a fish, make sure you pack your rain gear; you never know how good the fishing will be.