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Big Thompson River in Moraine Park inside Rocky Mountain National Park
All Colorado reports

Big Thompson

Photo: Wusel007 Opens in a new tab. · CC BY-SA 3.0

Should I go fishing?

Check the water temperature first.

Water temperature is unconfirmed. Use a stream thermometer; stop trout fishing at 70°F or warmer, or sooner if fish show stress.

Rating updatedRiver local time:

Why this recommendation?

USGS shows 34 cfs. The flow has been falling about 12% over about 6 hours. USGS marks this reading provisional and may revise it. USGS records for this date (1979-2025, 47 readings) show a typical middle range of 31 cfs to 50 cfs. Flow is within the typical range for this date, so weather, temperature, and access become the next checks.

Available live dataHighHow much of the live flow, weather, and alert data came back.
Confidence in this recommendationMediumWater temperature not verified; do not use this score to clear warm-water risk.
Usually checks again about every 45 minutes

If you go

Check first
Use RiverReports for quick flow shape, then use USGS 06741510 as the official downstream flow check before committing to the canyon.
Try
Start with short, high-percentage pockets before you cast to long obvious runs.
Leave when
Skip during muddy runoff spikes, lightning-heavy afternoons, or when lower canyon water is warm enough to stress trout.

Flow and weather

Showing server-checked river conditions while current readings refresh.
Flow
34 cfs
From the latest stored river check. Open the official source for the newest reading.
Air forecast
56°F
Next 24h high
72.0°F

NWS air forecast near

Rain chance
9%

This is an air forecast, not a river-temperature reading. Check the water with a stream thermometer before fishing in hot weather.

Latest stored weather check

Partly Cloudy

Wind
6 mph
Weather checked
More forecast and source details

Partly Cloudy

National Weather Service

Big Thompson forecast point

The National Weather Service forecast is temporarily unavailable.

Live data

Where these readings come from

RiverReports gauge: Big Thompson

Official USGS station Opens in a new tab.RiverReports gauge Opens in a new tab.Official NWS forecast Opens in a new tab.

Flies for this time of year

Seasonal starting points, not a live hatch report. Match what you see on the water.

See flies for every season
SeasonWhat to look forFlies to try

Each fly name opens its matching Fly Box guide.

More fishing tips

Methods, fish species and trip notes

How to fish Big Thompson today.

Stable summer and early fall flows usually offer the cleanest all-day trout fishing. During runoff, target softer seams and shorter sessions, and when the canyon is rising fast, choose another Front Range option.

Low clear water

Fish early and late with smaller dries, light nymphs, and longer leaders.

Moderate stable flow

Best all-around pocket-water condition for dry-dropper coverage.

Runoff or storm color

Stay near soft banks and eddies, fish bigger nymphs or streamers, or wait for the drop.

Warm afternoons

Lower canyon water can warm quickly. Carry a thermometer and end the trout plan if temperatures climb.

Wading, bank fishing or floating?
Access choicesNo single best option

Wading and Bank fishing have the same top score. Use current access, footing, weather, and local rules to choose.

Wading92/100

Wading is in play only where your chosen access has clear footing, legal entry, and no forced crossings.

Bank fishing92/100

Bank and edge fishing remains a practical low-commitment option if access is legal and footing is safe.

FloatingNot recommended

This report does not recommend floating this reach.

Full river report

Is Big Thompson worth the trip today? Check flow, weather, hatches, access, and rules for Colorado before you go.

The Big Thompson fishes best when you match your reach to runoff, canyon safety, and the current Rocky Mountain National Park or Colorado special fishing rule section you actually plan to fish.

Fishing words used on this page
U.S. Geological Survey (USGS) gauge
A USGS gauge is an official river station that measures flow or water height.
Cubic feet per second (cfs)
Cubic feet per second, or cfs, shows how much water passes the gauge each second.
Nymph
A nymph is a young water insect. Anglers also use the word for a fly that copies it.
Seam
A seam is the line where fast and slow water meet.
Blue-winged olive (BWO)
Blue-winged olives, or BWOs, are small mayflies that often hatch in cool or cloudy weather.
Caddis
Caddis are small water insects. The adults look a little like tiny moths.
Dry-dropper
A dry-dropper rig has a floating fly with an underwater fly tied below it.
Emerger
An emerger copies an insect as it rises from below the water toward the surface.
Midge
Midges are tiny flies and a common trout food, especially in cold water.
Pale morning dun (PMD)
Pale morning duns, or PMDs, are light-colored mayflies that often hatch in warmer months.
Why this call

Why this score

FlowHelps

USGS shows 34 cfs. The flow has been falling about 12% over about 6 hours. USGS marks this reading provisional and may revise it. USGS records for this date (1979-2025, 47 readings) show a typical middle range of 31 cfs to 50 cfs. Flow is within the typical range for this date, so weather, temperature, and access become the next checks.

SeasonHelps

Early fall: Often the best combination of stable flow, cool nights, and manageable pressure.

WeatherHelps

The current NWS air forecast is about 56F, and the next 24-hour high reaches about 72F. Partly Cloudy.

Public alertsHelps

No active NWS alert was returned for this forecast point.

Fishing usefulnessHelps

Skip during muddy runoff spikes, lightning-heavy afternoons, or when lower canyon water is warm enough to stress trout.

Trip notes

Check these before you choose a reach.

Best flows

Stable or dropping freestone flows with enough visibility to fish pockets and banks safely.

When to leave

Skip during muddy runoff spikes, lightning-heavy afternoons, or when lower canyon water is warm enough to stress trout.

Local plan

Base in Estes Park, check park rules and the lower gauge, then choose one upper reach and one canyon backup instead of trying to cover the entire river.

Backup water

Shift to Boulder Creek, Clear Creek, or a South Platte option if runoff or canyon safety does not line up.

Big Thompson access and rules.

Use these places as starting points. Open the access link below and check posted signs before you park or enter.

Before you go

Rocky Mountain National Park requires a Colorado fishing license for anglers 16 and older and lists specific catch-and-release and closed waters. Colorado's special fishing rule page also lists the Big Thompson from the base of Olympus Dam at Lake Estes downstream to Waltonia as artificial flies and lures only with immediate trout release.

Where to access the river

Moraine Park

Classic Rocky Mountain National Park meadow water. Check current park access and section-by-section fishing rules first.

Lake Estes to Waltonia area

Special fishing rule canyon stretch with many short stops, but parking and shoulder safety decide which pullouts are worth fishing.

Lower canyon near Loveland

Best used as a short-session option when the upper river is too crowded or still dropping.

  • US 34 provides the basic canyon area, but do not assume every turnout is a comfortable or legal fishing stop.
  • Inside Rocky Mountain National Park, a Colorado fishing license is required for anglers 16 and older and park-specific gear restrictions still apply.
  • Treat canyon wading as a short-session plan with clear entry and exit points instead of forcing long walks beside traffic or steep banks.

If this water does not fit the day, check another report before you start the drive.

ColoradoBoulder Creek fishing reportAnother Front Range small-river option when you want shorter casts and lower elevation access.ColoradoClear Creek Canyon and Golden fishing reportUse the Clear Creek report for the Golden and Clear Creek Canyon corridor, Golden gauge, current lower-reach advisories, access, and flies. It does not cover upper Clear Creek, the West Fork, or Clear Creek Reservoir.ColoradoSouth Platte River fishing reportBetter fallback for longer nymph-focused days when freestone runoff is still too pushy.
See all Colorado fly fishing reports

Sources and report details

Official agencies and primary river operators come first. Secondary tools are labeled so you know what carries the most weight.

Rules and closures

Check what is allowed, where the rule applies, and whether the river is open.

Flow and weather

Check the latest river reading and forecast before you leave.

Access and land

Check public entry points, land rules, and seasonal access changes.

More helpful links

Use these links for stocking, safety, and other local details.

See all 7 checked sources

Rules and closures

Check what is allowed, where the rule applies, and whether the river is open.

Flow and weather

Check the latest river reading and forecast before you leave.

Access and land

Check public entry points, land rules, and seasonal access changes.

More helpful links

Use these links for stocking, safety, and other local details.

Source check is old. Last checked . Open the official links now and check for changes.

See something wrong? Report a source problem. Please do not send private spots or private access notes.

How this report was checked

How this report was checked

Trip guidance checked

What was checked: This report uses official regulation, flow, weather, access, and public-land sources first, then adds practical planning guidance for fly anglers.

Live measurements and forecasts keep their provider timestamps. Rules, access, and trip guidance use the source-review date shown here. BlueStreamFly planning advice is editorial interpretation, not an agency notice.

First-hand experience: BlueStreamFly does not claim a first-hand visit or local field test for this report unless a real contributor is explicitly named and linked.

Quick questions

Is the Big Thompson a wade river or a float river?

This page is primarily a wade plan. Most anglers do best by fishing short public sections rather than trying to float the canyon.

Which flow source should I trust first?

Use RiverReports for quick trend reading and USGS 06741510 for official context, then adjust for the specific reach because upper park water can look different from the lower canyon.

What is the most important rule check?

Check both Rocky Mountain National Park fishing rules and Colorado's special fishing rule page if your day crosses the park boundary or the Lake Estes to Waltonia stretch.