Best Spots for Summer Rainy Day Reservoir Fishing: 4 Proven Tips from Real Anglers

Let’s be real—summer heat can turn reservoir fishing into a total drag. The water’s too warm, the fish are hiding in the depths, and you’re sweating through your gear before you even cast. But then the rain hits? Oh, magic happens. Rainy days aren’t just a break from the sun—they’re a fish’s version of a buffet and a spa day rolled into one. But wait—you can’t just plop down anywhere and expect a bite. I’ve learned this the hard way, trust me. Let’s break down the four game-changing rules I swear by for summer rainy day reservoir fishing, based on years of soaking wet, fish-filled days (and a few epic fails).

First: Ditch the “Deep Water Only” Summer Rule—Rain Changes Everything

Okay, let’s get one thing straight: on sunny summer days, you’d be crazy not to target deep water. The surface is sweltering, so fish bolt to the depths to cool off. I’ve spent hours with a 6.3m rod reaching for 5m+ depths, only to catch a few tiny sunfish. But rain? It flips the script faster than a fish flipping off your hook.

Why Shallow, Nearshore Spots Are Rainy Day Gold

Here’s the science (and the fishy logic):

• Rain cools the water—shallow areas drop temp fast, making them way more comfortable than the still-warm deep.
• Oxygen boost! Rain slaps the surface, mixing in fresh air. Fish go nuts for that extra O2.
• Food delivery! Rain washes bugs, seeds, and even small critters from the banks into the water. It’s like a free meal for the fish.

Last June, I was fishing at Wangkuai Reservoir in Hebei (yes, I travel for good spots—don’t judge) with my buddy Ma Jingxin. It was pouring, 23-25°C, and we grabbed 3.6m rods (super short for summer!) and fished 1.5m deep, 5m from shore. In four hours, we each landed 20+ fish: big crucian carp, yellow catfish, even a few small grass carp. Meanwhile, our friends Cao Yi, Zhou Hongyun, and Wu Kai were stuck in 4m deep water with 6.3m rods. They left with 4 carp total. Total bummer for them—total win for us.

Grass Is Your Friend—But Pick the Right Grass

Everyone knows the old saying: “Fish where the grass is.” But rainy days? Grass rules change. On sunny days, dense weed beds are fish paradises—shade, food, hiding spots. But rain? Dense grass turns into a fish’s worst nightmare.

Why Grass Edges Beat Grass Beds on Rainy Days

Here’s the tea: dense weeds + low pressure (rainy days = tropical low pressure) = no oxygen. Weeds need sunlight to make oxygen, and rain clouds block the sun. So those thick weed beds? They become stagnant, stinky, and totally unlivable for fish. Instead, fish bolt to the edges of dense grass—where the water’s open, oxygen is flowing, and food washes in from the banks.

I learned this the hard way last July. I was fishing a small reservoir near Tang County, targeting big carp. I found a huge weed bed and set up right in the middle of a “weed hole.” Three hours, zero bites. My buddy Wu Kai came over, looked at my spot, and said, “Dude, this grass is dead. Move to the edge.” I moved 2m to the grass edge, cast once, and landed a 2kg carp in 10 minutes. Game. Changer.

Pro tip: If you’re fishing sparse grass, pick the densest patches in the sparse area. Fish still want cover—just not the suffocating kind.

Sandy/Stony Bottoms > Muddy Bottoms—No Exceptions

Let’s talk about the gross stuff: muddy bottoms. On sunny days, they’re okay—maybe a little murky, but fish can handle it. But rain? Muddy bottoms turn into toxic waste dumps.

Why Muddy Bottoms Suck on Rainy Days

Rain makes groundwater rise, which pushes stinky gases (methane, hydrogen sulfide) from the mud up into the water. Fish hate that—they can’t breathe, and it smells like rotten eggs. I once fished a muddy bottom spot after a heavy rain. The water was brown, and I could smell the mud from 10m away. I cast three times, and the only thing I caught was a leaf. Total waste of time.

Sandy or stony bottoms? They stay clean. No stinky gases, no murky water, and fish love hanging out there. Plus, the banks are dry—you don’t have to wade through mud up to your knees. Win-win.

Inflow Areas = Fish Buffets—Don’t Miss These

This one’s a classic, but rainy days make it even better: “Fish go to inflows.” On sunny days, reservoir inflows are usually small—just a trickle from a stream. But rain? Inflows pop up everywhere: stream mouths, valley runoff, even low spots in the dam. And fish go crazy for them.

Why Inflows Are Rainy Day Hotspots

Three reasons fish can’t resist inflows:

• Food! Rain washes bugs, seeds, and even small fish into the reservoir through inflows. It’s a nonstop snack bar.
• Oxygen! Inflow water is fresh, cold, and full of oxygen.
• Cover! Inflow water is usually murky, so fish feel safe hiding there.

Last July, I was fishing Xiangshan Reservoir with Wu Kai. We started in 4m deep water (sunny day habit) and caught one tiny carp by noon. Then the rain picked up, and Wu Kai wandered up to the northwestern inflow—water from a forested valley, murky, 1m deep. He cast once, and a big carp almost pulled his rod into the water. We moved there immediately, and by sunset, we each had 20+ carp and grass carp. I even lost a monster—probably 5kg—because I didn’t set the hook fast enough. Total heartbreak, but totally worth it.

One thing to remember: Inflows can be shallow, so use a short rod (3.6-4.5m) and light line. You don’t need to cast far—fish are right at the inflow mouth.

So there you have it—my four go-to rules for summer rainy day reservoir fishing. I’ve tested these a dozen times, and they never let me down (well, almost never—last month I forgot my rain boots and sank up to my waist in mud. Oops). The key is to forget everything you know about sunny summer fishing—rain changes the rules, and you have to change with it.

Next time it rains on your fishing trip? Don’t pack up. Grab your short rod, head to the nearshore, find some grass edges, pick a sandy bottom, and check the inflows. You’ll be reeling in fish before you know it. And if you catch a monster? Tag me—I want to see it!