Iowa · United States

Rathbun Lake IA fishing forecast

69 Good of 100

Rathbun Lake IA is a freshwater fishing spot in Iowa, United States. Anglers here target Walleye, Crappie, Channel Catfish, Largemouth Bass. The most productive months are typically April, May, June, July, August, September, October.

Quick answer

Best monthsApril, May, June, July

Top speciesWalleye, Crappie, Channel Catfish

Score now69/100

Local rulesUnited States — Federal Waters

Today’s verdict

Ranks #191 of 644 spots FishRadar scored worldwide today

Trending down — 5 points below this spot’s 7-day average

Score confidence ±12 points, from 6 live signals

The statistical model disagrees with the physics model here today — treat this score with extra caution.

Helping the score most

Water temperature+15.0Wind+12.0Barometric pressure+4.4

Pressure trend

Pressure stable — fish feeding on their usual rhythm

Current conditions

Sea surface temp	21.5 °C
Wind	11 km/h from NNW, gusting 22 km/h
Pressure	1017 hPa
Cloud cover	7%
Chlorophyll	0.30 mg/m³
Salinity	0.0 PSU
UV index	4
Wind sea	0.0 m
Ground swell	0.0 m at 0 s

The water is running true to season — within a few tenths of the August average of 21.5 °C for this location. The water is mixed to about 20.0 m, with the thermocline below that.

Updated 1 h ago.

What the score means at Rathbun Lake IA

Rathbun Lake IA currently scores 69 out of 100 (Good). Water temperature is 21.5 °C. 6 forecast signals are active in this score.

Water temperature +15.0: how close the water is to this species mix’s comfort band
Wind +12.0: surface chop, oxygen and bait drift
Barometric pressure +4.4: falling pressure often triggers feeding
Thermocline +3.0: a defined layer stacks fish at one depth
Pre-storm bite +2.4: the classic feed before heavy weather
Moon phase +2.0: lunar feeding rhythm

What’s biting now

The model expects today: channel-catfish, white-perch, atlantic-sturgeon, golden-trout, rock-bass, brown-bullhead, pumpkinseed, grass-carp

[object Object] — Protected here — release immediately

Bite windows

Moon

Waxing Gibbous · 82% lit

Solunar day rating

50 / 100

Best months for Rathbun Lake IA:

Score history at this spot

26 days tracked at this exact location

Best recent day: 2026-08-14, 85/100

20 day(s) at 70+ in the tracked period

9 points below the same day last week

About this spot

Water type

Lake · Freshwater

Lakes have no tide, so target structure, drop-offs, and seasonal thermoclines where fish concentrate by depth and temperature.

Access & shore

Fishable from shore · beach

What you can catch

Walleye

Sander vitreus
Crappie

Pomoxis spp.
Channel Catfish

Ictalurus punctatus
Largemouth Bass

Micropterus salmoides

Best months by species at Rathbun Lake IA

WalleyeSander vitreus
CrappiePomoxis spp.
Channel CatfishIctalurus punctatus
Largemouth BassMicropterus salmoides

Typical months; local seasons and closures apply.

Local regulations

U.S. federal fisheries authority

United States — Federal Waters

Licensing:

saltwater-recreational — residents Federal Recreational Fishing License may be required in addition to state license when fishing federal (EEZ) waters., non-residents Same as residents. Many states require their own license even in federal waters.

FishRadar regulations are summaries only. Federal and state waters rules overlap — always verify current federal and state agency rules before fishing.