Rock Lake

Rock Lake

Ewan, Whitman County, WA
3.42mi²
1781ft
Directions
Lake Information

Rock Lake is a notable natural feature located in Eastern Washington and holds a unique distinction for being the deepest and largest among all scabland lakes formed as a result of the Missoula Floods. The lake spans an area of 2,189 acres and has a maximum depth of over 360 feet, although the official measurement remains uncertain. The origin of Rock Lake can be traced back to the Missoula Floods, which occurred during the last ice age. The floods were caused by the periodic rupturing of the ice dam that blocked the Clark Fork River in western Montana, leading to catastrophic floods that swept across the region. As a result of these floods, numerous scabland lakes were formed across the eastern parts of Washington, with Rock Lake being the deepest and largest among them. Despite its uncertain depth measurement, Rock Lake is renowned for its unique geological features and diverse aquatic life. The lake's depth and size have created an ideal habitat for a wide range of fish species, including trout, bass, and catfish. The lake's surrounding landscape is also rich in diverse flora and fauna, providing ample opportunities for nature enthusiasts to explore and observe the local ecosystem. The scenic beauty of Rock Lake and its surrounding area has also made it a popular destination for outdoor recreational activities such as fishing, boating, hiking, and camping. Visitors can enjoy fishing for the lake's abundant fish species, boating in its calm waters, or exploring the numerous trails and campsites located in the surrounding area. Overall, Rock Lake is a unique natural wonder that has played a significant role in the geological and ecological history of the region. Its deep waters, diverse aquatic life, and stunning surroundings make it a must-visit destination for nature enthusiasts and outdoor adventurers.

Read more

Current Conditions

90°F
Feels like 94°F
Clear
Today's High
96°F
Today's Low
58°F

Water Temperature

69°F
Updated: (Jul 5)
Sign in to contribute temps.

Latest Water Temperature Data: Current water temperature for Rock Lake is 69° Fahrenheit - providing real-time thermal conditions for fishing, swimming, and water recreation planning.

Current Snapshot

Wind4 mph W (Gust 9 mph)
Pressure
29.85 inHg
Visibility43 mi
Humidity19%
Cloud Cover0%

Forecast: Tuesday, Jul 8

Day 1 of 9

Hourly Insights

7 AM
66°
10 AM
84°
1 PM
92°
4 PM
96°

Temperature

High
96°F
Low
58°F

Precipitation

Chance0%
Amount0.00"
Typeclear

Wind

7 mph
Avg Speed
Gusts up to
20 mph
CalmModerateStrong
Max Speed13 mph

Sun, Moon & UV

Sunrise12:04 PM
Sunset3:47 AM
Moon PhasewaxingGibbous
Max UV Index9 (Very High)

Weather Forecast & Fishing Conditions at Rock Lake

Today's weather at Rock Lake features partly cloudy skies with temperatures ranging from 58°F to 96°F. Wind conditions will average 7 mph with gusts reaching up to 20 mph, creating excellent fishing conditions with calm waters. The UV index will reach 9 (Very High), and there's a 0% chance of precipitation. The current water temperature is 69°F (updated Jul 5), indicating that excellent conditions for bass and trout fishing. These conditions will significantly impact fish behavior and angling success throughout the day.

Lake Map Views

LakeMonster PRO

Try Premium Features

Find the fishing sweet spots! See detailed temperature readings throughout your lake.

No credit card required for preview

July 3rd 2025

Weather Forecast

Tuesday

96°F
58°F

Wednesday

88°F
64°F

Thursday

83°F
58°F

Friday

90°F
55°F

Saturday

93°F
60°F

Sunday

94°F
64°F

Monday

93°F
63°F

Tuesday

89°F
68°F

Wednesday

91°F
63°F
Tuesday - 7/8/2025
96°F
58°F
12am
66°F
69°F
29.84 hPa
3 mph
NNE
G: 4 mph
2am
62°F
69°F
29.84 hPa
4 mph
ENE
G: 5 mph
4am
58°F
69°F
29.84 hPa
5 mph
ENE
G: 7 mph
6am
60°F
69°F
29.87 hPa
4 mph
ENE
G: 6 mph
8am
74°F
69°F
29.89 hPa
4 mph
SSE
G: 8 mph
10am
84°F
69°F
29.89 hPa
8 mph
SSW
G: 11 mph
12pm
90°F
69°F
29.87 hPa
11 mph
SW
G: 17 mph
2pm
93°F
69°F
29.85 hPa
13 mph
SW
G: 20 mph
4pm
96°F
69°F
29.81 hPa
12 mph
SW
G: 19 mph
6pm
96°F
69°F
29.78 hPa
10 mph
WSW
G: 19 mph
8pm
89°F
69°F
29.78 hPa
6 mph
WSW
G: 11 mph
10pm
78°F
69°F
29.81 hPa
5 mph
W
G: 13 mph

Water Temperature History

Trends for Rock Lake

Current Temp

69°F

Measured on Jul 2

Latest recorded surface temperature.

Lowest in Period

37°F

On Jan 19

Coldest point in the Last 12 Months.

Average in Period

52°F

Typical temp during the Last 12 Months.

Temperature Trend: Last 12 Months

Surface temperature over the selected period.

Key Observations (Last 12 Months)

  • Warmest avg: July (76°F).
  • Coolest avg: January (39°F).
  • Rapid warming often occurs: April → May (+14°F).
  • Sharpest cooling trend: September → October (-13°F).

Weather Forecast

Wind speed and pressure trends

Hourly Wind Forecast

12am1am2am3am4am5am6am7am8am9am10am11am12pm1pm2pm3pm4pm5pm6pm7pm8pm9pm10pm11pm05101520

Wind Direction

23°

Pressure

1011 mb

Cloud Cover

0%

Visibility

24 miles

Daily Pressure Forecast

TueWedThuFriSatSunMonTueWed0.008.8617.7226.5835.44
Go Premium
Better lake days, better fishing, better you with LakeMonster Pro
Relaxing app background
LakeMonster App Icon
Get a 7 day free trial

Frequently Asked Questions About Rock Lake

Get accurate, up-to-date information about conditions at Rock Lake.