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Lake Merwin Fishing Report

Updated Fri, Sep 4, 2026 from live gauge and weather data

The Lewis River's tiger den: Merwin's fjord-green water hides Washington's tiger muskies and kokanee under Mount St. Helens' shadow.

2/5
Slow. Work for them.Conditions favor short windows and patient fishing.
Water temp
~66 F est.
Air / High
66 / 70 F
Wind
SE 1 mph

Sources: Open-Meteo, solunar calculated for these coordinates.

Satellite view
Friday
4
September 2026

Today's Fishing Report

Generated this morning from live readings: gauge, weather model, sun and moon. A fresh report is published here every morning.

2/5Slow. Work for them.Conditions favor short windows and patient fishing.

Lake Merwin sits in the sweet spot of the season: active fish and workable weather. Today brings clear skies, wind SE around 1 mph, rising pressure near 1013 hPa and a high of 70. Water sits around 66 F for the season (estimated). With the last quarter, the solunar majors run 5:39 AM-7:39 AM and 5:39 PM-7:39 PM: the windows to build the day around.

The plan, species by species

MuskellungeExcellent

Bucktails and rubber over cabbage and rock bars; moon majors matter here more than anywhere.

Smallmouth bassGood

Peak season. Tubes, jerkbaits and swimbaits around gravel points, boulders and current seams.

WalleyeGood

Jig and minnow on rock reefs and points; the evening bite on wind-blown shores is the one to plan around.

Yellow perchFair

Drifting flats and weed edges with small jigs tipped with bait.

Tomorrow: Similar at 71 F with a rain chance. The solunar majors shift about 50 minutes later.Next report: Sat, Sep 5, 6:30 AMHow this report is made →

Water and weather

Live readings.

No live gauge on this water

Conditions here are modeled from weather, season and the nearest stations. Water readings appear when a USGS gauge is available.

304050607080JanMarMayJulSepNovSep, ~66 F now

Right now

Latest readings

Air temp66 F
High / Low70 / 53 F
WindSE 1-7 mph
Pressure1013.3 hPa, rising
Sky / Rain15% cloud, 40%
Sunrise / Sunset06:34 / 19:42
MoonLast Quarter, 50%
Water temp (seasonal)~66 F est.

Bite planner

Hour-by-hour bite forecast for today. Tap a bar to see why.

5 AM8 AM11 AM2 PM5 PM8 PMsunrisesunset

Next 7 days

Tap a day for the detailed outlook.

Fri Sep 4 · Rain, 70/53 F, wind 9 mph, rain 40%

Fair or better. A 9 mph breeze puts a working chop on the banks it hits: fish the wind-blown side.

Species guide

The species that matter on Lake Merwin: seasons, structure and how to fish each one. Today's ratings live in the report above.

Smallmouth bass illustration

Smallmouth bass

Best: May-Oct

Current and rock. Finds gravel flats, boulders and drop-offs, and fights far above its weight. Peak season. Tubes, jerkbaits and swimbaits around gravel points, boulders and current seams.

Muskellunge illustration

Muskellunge

Best: Sep-Nov

The fish of ten thousand casts. Weed edges, rock bars and big-water structure. Bucktails and rubber over cabbage and rock bars; moon majors matter here more than anywhere.

Walleye illustration

Walleye

Best: May-Jun, Oct

The glass-eyed prize of northern lakes. Low light, wind-blown structure and live bait. Jig and minnow on rock reefs and points; the evening bite on wind-blown shores is the one to plan around.

Yellow perch illustration

Yellow perch

Good most of the year

The great lakes and northern panfish staple. Schools tight to bottom; where you catch one there are fifty. Drifting flats and weed edges with small jigs tipped with bait.

When to come: the Lake Merwin calendar

Activity by species and month, and how the water warms through the year. Tap any cell.

Species activity by month

1 = slow, 5 = peak. Current month highlighted.

J
F
M
A
M
J
J
A
S
O
N
D
Smallmouth bass
Muskellunge
Walleye
Yellow perch
SlowPeak

Water temperature through the year

Typical surface temperature for this water type; today is around 66 F (estimated, not a reading).

304050607080JanMarMayJulSepNovSep, ~66 F now

Angler reports

Real reports from real anglers, reviewed before publishing. The water log below tracks each day automatically.

No angler reports yet this weekBe the first: your report helps every angler who checks Lake Merwin today, and we feature the best catch of the week.

Water log, last days

Auto-logged from live data
Thu, Sep 3

4/5 Good. Solid day ahead. Stable-to-falling pressure and workable wind line things up. Smallmouth bass led the card at excellent. High of 63 F, wind to 8 mph.

Wed, Sep 2

4/5 Good. Solid day ahead. Stable-to-falling pressure and workable wind line things up. Smallmouth bass led the card at excellent. High of 65 F, wind to 8 mph.

Tue, Sep 1

4/5 Good. Solid day ahead. Stable-to-falling pressure and workable wind line things up. Smallmouth bass led the card at excellent. High of 66 F, wind to 8 mph.

Where roughly, what depth, what bait. Skip anything you want to keep secret.
Only used to send you this water's report each week. No spam, ever.

Before you go

License

Washington requires a valid fishing license for adults. Buy online from the state agency; one-day options exist for visitors.

Regulations

Washington license. Tiger muskie: 50-inch minimum: kokanee limits: check WDFW.

Access

Speelyai Bay, Cresap Bay PacifiCorp parks.

About this water

4,090 acres on the Lewis River, Clark/Cowlitz counties, WA. The tiger fjord.

Fishing Lake Merwin: the full guide

The Lewis fjord

Merwin pools the Lewis River's lower canyon: 4,000 deep green acres winding fjord-like below St. Helens' flank: Washington's tiger-muskie flagship (stocked to crop the pikeminnow: grown into a trophy fishery) over kokanee schools and coastal cutthroat margins.

Tiger program

The tigers patrol the weedy coves and downed timber (Speelyai Bay the storied ground): bucktails and gliders spring through fall, figure-eights mandatory, releases near-universal (one over 50 inches the legal bar: check current). Fifty-inch fish exist: the state record class swims here.

Kokanee and cutts

The kokanee fleet trolls the main channel (dodgers at 30-60 feet: a dependable meat game), coastal cutthroat work the tributary mouths (trolled spoons shallow, spring and fall), and the odd bull trout demands ID-and-release respect: Lewis system rules run protective.

Lewis practicalities

PacifiCorp's parks serve the lake (Speelyai, Cresap): the canyon walls limit bank access (boats rule): and the volcano's tourism passes obliviously overhead. Yale and Swift stack upstream: the three-reservoir Lewis ladder fills a weekend.

Common questions

How big do Merwin tigers get?

State-record class: 50-plus-inch fish patrol the coves. Speelyai's weed edges are the storied hunt: bring the figure-eight faith.

What else does Merwin fish?

Kokanee at depth and cutthroat at the creek mouths: the tiger fame hides a steady two-program lake. The canyon scenery fishes free.

Can you fish Merwin from shore?

The PacifiCorp parks offer limited bank at Speelyai and Cresap: kokanee stay boat-water but cutthroat cruise the accessible mouths. The canyon's geometry makes a small boat the honest ticket: rentals nearby seasonal.

Is fishing good at Lake Merwin right now?

Check the daily report at the top of this page: it is regenerated every morning from live data. Today's read: Slow. Work for them. Conditions favor short windows and patient fishing.

Nearby waters

Kalama River18 miLewis River19 miCowlitz River25 miSandy River37 miRiffe Lake38 miDrano Lake42 mi
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