Fly Fishing in the Rain: Why Some of the Best Fishing Happens in Bad Weather

Most fly fishers check the weather forecast and cancel when they see rain. That is understandable — nobody dreams about standing in a river getting soaked. But the anglers who fish through the rain know something the fair-weather crowd does not: some of the best fishing of the year happens when the sky goes dark and the water starts falling.

Rain changes everything about the river ecosystem in ways that overwhelmingly favor the angler. Understanding why fish feed more aggressively in wet weather — and how to adjust your approach — can turn a miserable-looking day into the best outing of the season.

Why Fish Feed More in the Rain

Increased Bug Activity

Rain triggers insect hatches. As barometric pressure drops ahead of a storm, aquatic insects become more active. Mayflies, caddis, and stoneflies sense the pressure change and begin emerging in numbers they would not during a bright, stable day. Terrestrial insects — ants, beetles, grasshoppers — get knocked off overhanging vegetation and into the water by wind and rain.

The result is a buffet. Fish that were holding deep and being selective during a bluebird afternoon will move to feeding positions and eat opportunistically once the rain starts. You go from casting to fish that are not interested to casting to fish that are actively looking for food.

Reduced Visibility

Rain dimples the surface of the water, breaking up the window through which fish see the world above. This makes fish less cautious — they cannot inspect your fly as carefully, your leader is harder for them to see, and your shadow and silhouette above the water are obscured. You can get closer, present less perfect drifts, and still get eats.

For the same reason, fish become less wary of predators (birds, osprey) during rain. Overhead threats are harder to spot, so fish move from sheltered lies into open feeding lanes where they are normally too exposed during sunny conditions.

Dissolved Oxygen

Rain increases dissolved oxygen in the water, especially in warmer months when oxygen levels can be low. Higher oxygen levels make fish more active and metabolically ready to feed. This is particularly noticeable in still water — ponds and lakes that are sluggish in summer heat can come alive during a rain event as oxygen levels spike.

Runoff Delivers Food

As rain hits the surrounding landscape, it washes terrestrial insects, worms, and organic matter into the river. This runoff creates a conveyor belt of food that fish learn to exploit. Seams where tributaries or runoff channels enter the main river become especially productive during and immediately after rain.

Dropping Barometric Pressure

Fish have swim bladders that are sensitive to pressure changes. When barometric pressure drops (as it does before and during storms), the swim bladder expands slightly, which appears to make fish uncomfortable at their current depth. They move shallower and feed more actively, possibly to relieve the sensation. This is anecdotal but widely reported by experienced anglers across species and water types.

What to Throw

Dry Flies: Bigger and Bushier

This is not the time for a size 22 BWO on 7X tippet. Fish are less selective in the rain, so size up and use patterns that are visible to both you and the fish in low-light conditions.

Top patterns:

• Stimulator (size 8–12): High-floating, visible, imitates stoneflies and general large insects. The go-to searching pattern in rain.
• Elk Hair Caddis (size 10–14): Rides high, easy to see, and caddis hatches are often triggered by rain.
• Chubby Chernobyl (size 8–10): Unsinkable, high-visibility foam body. If fish are looking up, they will see it.
• Parachute Adams (size 12–16): The white parachute post is visible even in rain-dimpled water.

Nymphs: Get Deeper

If fish are not coming to the surface, the rain is still helping you underground. Increased flow pushes nymphs off the bottom, and fish feed sub-surface with less caution.

Top patterns:

• Pat's Rubber Legs (size 6–10): Heavy stonefly nymph that gets down fast. Excellent in the increased flow that comes with rain.
• Hare's Ear (size 12–16): General-purpose mayfly nymph. Works in any condition but especially effective when insects are dislodged by current.
• San Juan Worm (size 10–14): Worms get washed into rivers during rain. Fish know this. There is no shame in fishing a worm pattern when it is raining.

Streamers: The Rain Advantage

Streamers — which imitate baitfish, sculpin, and leeches — are particularly effective in rain because:

1. Reduced visibility makes fish less cautious about chasing
2. Increased flow activates larger predatory fish
3. The surface disturbance covers your retrieve motion

Top patterns:

• Woolly Bugger (size 6–10): The universal streamer. Olive or black. Strip it slowly through deep runs and pools.
• Sculpzilla (size 4–8): Imitates a sculpin getting pushed around by current. Dead-drift or slow strip along the bottom.

Gear to Stay Dry

Fishing in the rain is only enjoyable if you are prepared for it. The wrong gear turns a productive day into hypothermia risk.

Wading jacket: A quality waterproof breathable jacket (Simms, Patagonia, Orvis) is the single most important piece of rain fishing gear. Look for Gore-Tex or similar membrane, sealed seams, a hood that fits over a cap, and pit zips for ventilation. A $300 jacket that keeps you dry for 6 hours on the water is worth every cent.

Waterproof hat: A baseball cap or wide-brim hat keeps rain out of your eyes and off your face. A hood alone is not enough — peripheral vision matters for casting and wading safety.

Layers underneath: Wool or synthetic base layers, never cotton. Cotton absorbs water and loses all insulating properties. Merino wool stays warm even when damp. In warmer rain (summer), a lightweight synthetic shirt under your wading jacket is sufficient.

Waterproof pack or dry bag: Your phone, snacks, extra flies, and car keys need to stay dry. A waterproof sling pack or a simple dry bag solves this.

Wading boots with good traction: Wet rocks are more slippery than normal. If you use felt-soled boots, they actually grip better when wet. Rubber-soled boots with tungsten studs offer the best all-condition traction.

Polarized sunglasses (yes, in the rain): They still cut glare from the water surface, they protect your eyes from errant hooks during casts, and they help you read water structure. Amber or copper lenses work best in low light.

When to Head Home: Safety Considerations

Rain fishing is productive and rewarding, but there are conditions where the responsible decision is to get off the water.

Lightning: If you hear thunder, see lightning, or see rapidly darkening skies with anvil-shaped clouds, get off the water immediately. You are standing in a river holding a 9-foot carbon fiber lightning rod. Lightning kills more anglers than any other weather event. The rule: if thunder follows lightning by less than 30 seconds, the storm is within 6 miles and you should already be in your vehicle.

Rapidly rising water: Light to moderate rain is fine. Heavy rain that causes visible water rise is dangerous. River levels can spike feet in minutes during heavy storms, especially in smaller streams and tailwaters. If you notice the water rising around your wading boots, getting muddier, or carrying more debris than when you started, get to shore and assess. Flash flood warnings are not suggestions.

Cold rain plus wind: Rain in 40-degree weather with wind is hypothermia territory. If you are shivering, cannot feel your fingers, or are having trouble tying knots, your body is telling you to stop. No fish is worth a medical emergency.

Blown-out conditions: Once enough rain falls to turn the river chocolate brown and raise it significantly, the fishing is over until things settle. Fish cannot see your fly and are hunkered down. This usually happens during or after heavy, sustained rain. The fishing will be excellent once the water starts to drop and clear — often 12–48 hours after the rain stops.

Key Takeaways

• Rain triggers insect activity, reduces fish caution, increases dissolved oxygen, and washes food into the river — all of which make fish more active and less selective
• Size up your dry flies (Stimulators, Elk Hair Caddis, Chubby Chernobyls) and focus on visibility over delicacy
• San Juan Worms and stonefly nymphs are particularly effective during rain as worms and nymphs get dislodged by current
• Streamers benefit from reduced visibility — fish are more willing to chase in rain
• A good waterproof wading jacket and layering system are essential for comfort and safety
• Leave the water immediately for lightning, rapidly rising water, or signs of hypothermia
• Some of the best fishing of the year happens in the first hour of a moderate rain — be prepared and be there

Affiliate Disclosure: This article may contain affiliate links. If you make a purchase through these links, we may earn a small commission at no extra cost to you. We only recommend products we genuinely believe in. This helps support our work and allows us to continue providing free content.