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Boulder River Fishing Report

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

The Absaroka jewel: a boulder-strewn freestone falling out of the wilderness to the Yellowstone, thick with wild browns and rainbows.

2/5
Slow. The wind owns today.32 mph gusts make boat control the real battle.
Flow
103 cfs
Air / High
55 / 56 F
Wind
W 24 mph

Sources: USGS gauge 06200000, 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.

2/5Slow. The wind owns today.32 mph gusts make boat control the real battle.

Boulder River is in its winter mode: slow, deep and deliberate. The river is running 103 cfs, dropping and clearing. Today brings cloud cover, wind W around 24 mph, rising pressure near 1004 hPa and a high of 56. Water sits around 47 F for the season (estimated). With the waxing gibbous, the solunar majors run 9:57 AM-11:57 AM and 10:28 PM-12:28 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: Cooler at 47 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

Montana requires a fishing licence from age 12, from $31.00 for residents. What a Montana licence costs and where to buy it β†’

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

Water and weather

Live readings from Boulder River at Big Timber.

Flow, last 30 days

USGS gauge 06200000.

7894110103 cfs09/2310/0310/1310/23

Today’s flow against 77 years of October 23

At 103 cfs, the flow at USGS gauge 06200000 (Boulder River at Big Timber) is below the 5th percentile for the date: much below normal. In half of the 77 years of approved record the daily mean on October 23 was below 214 cfs; the highest was 469 cfs and the lowest 100 cfs.

p10 133median 214p90 320

Percentiles of the daily mean flow for this date, from the USGS Water Data Statistics API for gauge 06200000; 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 temp55 F
High / Low56 / 31 F
WindW 24-33 mph
Pressure1003.7 hPa, rising
Sky / Rain100% cloud, 52%
Sunrise / Sunset07:47 / 18:20
MoonWaxing Gibbous, 91%
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 PMsunrisesunset

Which day to fish Boulder River this week

The best day on Boulder River this week looks like Saturday Oct 24, at 3 out of 5, against 2 today.

Best day this week: Saturday, Oct 24 β€” fair at 3/5, rising pressure behind a front, typically the slowest.

Today, Oct 23 β€” Tough

32 mph gusts make boat control the real battle.

Solunar majors
9:57 AM-11:57 AM and 10:28 PM-12:28 AM
Minor period
4:22 AM-5:22 AM
Sun
07:47 to 18:20
Moon
Waxing Gibbous, 91% lit
Sky and wind
Rain, 32 mph
Rain chance
52%

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

Species guide

The species that matter on Boulder 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 Boulder 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 Boulder 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 70 F, wind to 10 mph.

Wed, Oct 21

2/5 Slow. Work for them. Conditions favor short windows and patient fishing. Rainbow trout led the card at excellent. High of 67 F, wind to 8 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 65 F, wind to 16 mph.

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

License

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

Regulations

Montana license + AIS pass. Standard western district trout rules: check FWP for the Yellowstone drainage.

Access

Accesses along Hwy 298: Boulder Forks, Big Rock, Natural Bridge SP; wilderness trailheads above.

About this water

Absaroka freestone joining the Yellowstone at Big Timber. The quiet sibling of the famous valley.

Fishing Boulder River: the full guide

Fifty miles of gradient

The Boulder drops out of the Absaroka-Beartooth Wilderness in a staircase of pocket water: plunge pools, boulder gardens and slicks holding wild browns and rainbows that see a fraction of the Yellowstone's traffic. The lower river (Natural Bridge down to Big Timber) floats in high water; most of the year it is a wade fishery of the classic Montana kind.

Pocket-water school

This is high-stick country: attractor dries with droppers, short drifts behind every rock, and fish that decide fast. The river teaches efficiency: hit the soft spots, move, repeat. Salmonflies and goldens climb the canyon in late June; hoppers own the August banks; October streamers move the big browns that run up from the Yellowstone.

Access rhythm

Highway 298 shadows the river south from Big Timber: fishing accesses and bridge crossings chain the lower thirty miles, and the McLeod stretch is the social center (the Road Kill Bar counts as angling infrastructure). Above Natural Bridge Falls the water turns wilderness: foot access, cutthroat, and solitude measured in trail miles.

A Boulder year

Runoff clears by late June most years: the window runs tight and sweet through October. July: stones and attractors. August: hopper banks and cold mornings. September-October: streamer browns and empty water. Winter belongs to the canyon and the whitefish: locals nymph the slicks on warm afternoons.

Common questions

How does the Boulder compare to the Yellowstone?

Smaller, steeper, more intimate: pocket water instead of big drifts, wading instead of boats, and browns that average honest with real surprises. Fish both: they are twenty minutes apart.

When can you float the Boulder?

Only in the higher flows of early summer, lower river only: most of the season it is a wading river. The pocket water is the point: bring studded boots and a staff.

Is fishing good at Boulder River right now?

Check the daily report at the top of this page: it is regenerated every morning from live data. Today's read: Slow. The wind owns today. 32 mph gusts make boat control the real battle.

Nearby waters

Yellowstone River29 miGallatin River75 miJefferson River77 miEnnis Lake86 miCanyon Ferry Lake89 miMadison River90 mi

Where this page's numbers come from

River and reservoir readings
USGS 06200000 β€” Boulder River at Big Timber
Read from the USGS Water Data API (api.waterdata.usgs.gov). Latest value timestamped 2026-10-23 at 19:00 UTC.
Weather and pressure
Open-Meteo forecast model
Queried at 45.7470, -109.9650 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.
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 guide was drafted with AI assistance. Unlike our newer pages, it does not yet list the official pages its facts were checked against: that audit is under way, and anything it cannot verify will be 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.