Lake Merwin

Lake Merwin

Na, WA

59°F
64°
7 mph76°/46°

Right Now

64°

Mostly Clear

Water

59°

Wind

7 mph

NNW

Gusts

14 mph

Pressure

29.90

steady

Forecast - Wed, May 27

7am
52°
10am
64°
1pm
72°
4pm
76°

High / Low

76° / 46°

Wind

5 mph

gusts 21 mph

Precip

0%

UV

7

Sunrise

12:26 PM

Sunset

3:48 AM

Today Read

Lake Merwin

Wind read

Calm

5 mph avg

Water read

59°

Cool-water mix

Air range

46° / 76°

today

Precip

0%

low concern

Today's forecast for Lake Merwin has calm wind, 46F to 76F air temperatures, 0% chance of precipitation, and 59F water.

AI lake plannerFishableChecking questions

Ask what to do at Lake Merwin today.

The planner reads this page's water temp, forecast, fish species, solunar timing, reports, and imagery context so you can decide what to throw, when to go, and when to move.

Today's AI read

Active-water pattern for Rainbow trout / Smallmouth bass

66 confidence

Active temps make wind edges, shallow cover, and feeding windows more important. Wind is not the main constraint, so timing and presentation can drive the plan. With a weak solunar score, favor stable weather windows.

Uses this lake data

Current water temp: 59°FWater temp history: 468 readingsHourly weather: 224 hoursSolunar timing: 2/5Fish species: 4 listedSatellite imagery: 402 captures

Trip read from the AI planner

Fishing Forecast

waxing gibbous

2/5

Major

7:00 AM - 7:00 AM

Minor

12:09 AM - 1:39 AM

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May 11, 2026

Fish Species

4

Water Temperature History

Current

63°

Jun 7

Low

38°

Feb 5

Average

54°

Last 12 Months

Warmest avg: July (71°F)

Coolest avg: February (39°F)

Rapid warming: MarchApril (+8°F)

Sharpest cooling: OctoberNovember (-13°F)

Weather Forecast

Wind speed, gusts, and pressure trends for trip timing.

Hourly Wind Forecast

27

12am - 11pm

Wind SpeedWind Gust
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Peak Wind

10 mph

3pm

Peak Gust

21 mph

highest gust

Pressure

29.92 inHg

rising

Visibility

17 mi

26% clouds

Tap chart for details, swipe left or right for different days.Tap chart for details • Swipe for different days

Daily Pressure Forecast

Pressure
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Tap chart points for pressure details

Nearby Lakes

FAQ

About Lake Merwin

Lake Merwin covers 3840.00 acres (6.00 square miles)

Lake Merwin is located in Na, Cowlitz County, WA. It is accessible to the public for outdoor activities.