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South Fork Boise River Fishing Report

Updated Fri, Oct 23, 2026 from live gauge and weather data

The South Fork Boise below Anderson Ranch Dam: a Reclamation tailwater northeast of Mountain Home whose flows follow releases from a 474,900-acre-foot reservoir.

3/5
Fair. Fish the windows.A steady pattern: dawn and dusk carry the day.
Flow
309 cfs
Air / High
42 / 49 F
Wind
WNW 12 mph

Sources: USGS gauge 13190500, Open-Meteo, solunar calculated for these coordinates.

Satellite view
Friday
23
October 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.

3/5Fair. Fish the windows.A steady pattern: dawn and dusk carry the day.

South Fork Boise River asks for patience today: short windows, precise presentations. The river is running 309 cfs, steady over the week. Today brings cloud cover, wind WNW around 12 mph, steady pressure near 1014 hPa and a high of 49. Water sits around 47 F for the season (estimated). With the waxing gibbous, the solunar majors run 10:20 AM-12:20 PM and 10:50 PM-12:50 AM: the windows to build the day around.

The plan, species by species

Rainbow troutExcellent

In cold water rainbows use the deepest pools in rivers (Vermont), so slow, deep drifts there are the usual approach; Michigan DNR notes lake rainbows are also taken with bait or by jigging through the ice.

Brown troutExcellent

Below 50Β°F, fish slowly through the deeper pools; in early spring on the Great Lakes, Michigan DNR notes browns are often caught inshore before other species start biting.

Tomorrow: Warmer at 54 F. The solunar majors shift about 50 minutes later.Next report: Sat, Oct 24, 6:30 AMHow this report is made β†’

Before you go

Idaho requires a fishing licence from age 14, from $35.50 for residents. What a Idaho licence costs and where to buy it β†’

Chasing rainbow trout here? Check the size and bag limits with IDFG before you keep anything. The season dates for Idaho, read off the agency, are on the Idaho seasons page.

Water and weather

Live readings from South Fork Boise River at Anderson Ranch Dam, ID.

Flow, last 30 days

USGS gauge 13190500.

295301307309 cfs09/2310/0310/1310/23

Today’s flow against 83 years of October 23

At 309 cfs, the flow at USGS gauge 13190500 (South Fork Boise River at Anderson Ranch Dam, ID) is at the 69th percentile for the date: normal. In half of the 83 years of approved record the daily mean on October 23 was below 299 cfs; the highest was 1,300 cfs and the lowest 1 cfs.

p10 54median 299p90 480

Percentiles of the daily mean flow for this date, from the USGS Water Data Statistics API for gauge 13190500; today’s reading is the latest instantaneous value. Classes follow the ones the USGS used on its WaterWatch maps (retired at the end of 2025): below 10th, much below normal; 10th–24th, below; 25th–75th, normal; 76th–90th, above; over 90th, much above.

Right now

Latest readings

Air temp42 F
High / Low49 / 38 F
WindWNW 12-21 mph
Pressure1013.7 hPa, steady
Sky / Rain100% cloud, 51%
Sunrise / Sunset08:05 / 18:45
MoonWaxing Gibbous, 91%
Water temp (gauge)51 F USGS
Water temp (seasonal)~47 F est.

Bite planner

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

5 AM8 AM11 AM2 PM5 PM8 PMsunrisesunsetPRIMEPRIME

Which day to fish South Fork Boise River this week

Today is the pick of the week on South Fork Boise River, at 3 out of 5.

Best day this week: today, Oct 23 β€” fair at 3/5, steady pressure, neither help nor hindrance.

Today, Oct 23 β€” Fair

A steady pattern: dawn and dusk carry the day.

Solunar majors
10:20 AM-12:20 PM and 10:50 PM-12:50 AM
Minor period
4:45 AM-5:45 AM
Sun
08:05 to 18:45
Moon
Waxing Gibbous, 91% lit
Sky and wind
Showers, 16 mph
Rain chance
51%

Forecast-based scores, less reliable further out: how the score is built.

Species guide

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

Rainbow trout illustration

Rainbow trout

Spring and fall in most lakes; rivers fish year-round while the water stays cool

A cold-water trout native to Pacific drainages from Alaska to Baja California, now stocked in most states and fished in rivers, tailwaters and lakes. In cold water rainbows use the deepest pools in rivers (Vermont), so slow, deep drifts there are the usual approach; Michigan DNR notes lake rainbows are also taken with bait or by jigging through the ice.

Brown trout illustration

Brown trout

Spring along Great Lakes shorelines; low light and overcast days in rivers; fall spawning runs

A European trout first stocked in the US in 1883 and now fished in rivers and lakes nationwide; it tolerates warmer water than other trout, and mature stream fish feed mostly at night. Below 50Β°F, fish slowly through the deeper pools; in early spring on the Great Lakes, Michigan DNR notes browns are often caught inshore before other species start biting.

When to come: the South Fork Boise River 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
Rainbow trout
Brown trout
SlowPeak

Water temperature through the year

Typical surface temperature for this water type; today is around 47 F (estimated, not a reading).

30405060JanMarMayJulSepNovOct, ~47 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 South Fork Boise River today, and we feature the best catch of the week.

Water log, last days

Auto-logged from live data
Thu, Oct 22

3/5 Fair. Fish the windows. A steady pattern: dawn and dusk carry the day. Rainbow trout led the card at excellent. High of 68 F, wind to 22 mph.

Wed, Oct 21

3/5 Fair. Fish the windows. A steady pattern: dawn and dusk carry the day. Rainbow trout led the card at excellent. High of 70 F, wind to 15 mph.

Tue, Oct 20

3/5 Fair. Fish the windows. A steady pattern: dawn and dusk carry the day. Rainbow trout led the card at excellent. High of 70 F, wind to 15 mph.

Where roughly, what depth, what bait. Skip anything you want to keep secret.
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Before you go

License

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

Regulations

Idaho fishing license. IDFG's Southwest Region rules carry special regulations for the South Fork below Anderson Ranch Dam, including bait, hook, season and size restrictions. IDFG's website could not be reached on Oct. 8, 2026; read the current IDFG rules before fishing.

Access

Reclamation operates the dam; check the Boise National Forest for road and site conditions before driving in.

About this water

Tailwater of Anderson Ranch Dam, Elmore County, ID. Flow on this page comes from USGS gauge 13190500, South Fork Boise River at Anderson Ranch Dam.

Fishing South Fork Boise River: the full guide

Anderson Ranch Dam

Reclamation's Anderson Ranch Dam stands 456 feet high on the South Fork of the Boise River, 28 miles northeast of Mountain Home. When it was completed in 1950 it was the world's highest earthfill dam. It serves irrigation, power and flood and silt control and holds 474,900 acre-feet, 413,100 of them active storage, so flows in the river below follow its releases.

Watching the flow

USGS gauge 13190500 measures the South Fork at Anderson Ranch Dam. On Oct. 8, 2026 it read 295 cubic feet per second, with water at about 51 degrees F.

Common questions

How tall is Anderson Ranch Dam?

456 feet, according to Reclamation; it was the world's highest earthfill dam when it was finished in 1950.

Where is the South Fork's flow measured?

At USGS gauge 13190500 just below Anderson Ranch Dam.

Is fishing good at South Fork Boise River right now?

Check the daily report at the top of this page: it is regenerated every morning from live data. Today's read: Fair. Fish the windows. A steady pattern: dawn and dusk carry the day.

Nearby waters

Anderson Ranch Reservoir2 miLucky Peak Reservoir30 miBoise River45 miPayette River54 miMagic Reservoir57 miLake Lowell62 mi

Where this page's numbers come from

River and reservoir readings
USGS 13190500 β€” South Fork Boise River at Anderson Ranch Dam, ID
Read from the USGS Water Data API (api.waterdata.usgs.gov). Latest value timestamped 2026-10-23 at 18:15 UTC.
Weather and pressure
Open-Meteo forecast model
Queried at 43.3500, -115.4800 in this water's own timezone. A model, not an observation.
Moon and solunar windows
Calculated on this site
Astronomical calculation from these coordinates and the date, not a third-party feed. How much weight it deserves.
Pages checked
The facts in the written guide were checked against these pages, from the agencies and operators that manage the water, on October 8, 2026. Anything we could not verify was taken out.
The written guide on this page
Pablo Ruiz Quintero
How this page was made. The daily report is computed by our scoring engine from live readings; nobody types it. The written text was drafted with AI assistance from the official pages listed above, and its facts were checked against those pages by automated verification on October 8, 2026; anything that could not be verified was taken out. Pablo Ruiz Quintero sets every guideline, the data-verification system and the minimum standards a page must meet to be published, reviews page structure and approves what goes live; the responsibility is his, and the AI carries out the work. We work this way because it is how one person can keep every page current with named sources. Errors are published in the verification log; the full policy is in the editorial policy.

Readings refresh on a 30-minute window. The full method, with every figure and its source, is on how our reports are made. Something wrong here? Tell us and it goes in the log with the date.