Wade0/100
Wading is the most sensitive plan today. Use protected edges only, avoid crossings, and downgrade quickly if clarity or current feels wrong.
All Colorado reports
Fly fishing report · West
North St. Vrain
Is North St. Vrain worth the trip today? Check flow, weather, hatches, access, and rules for Colorado before you go.
See the flow chart ↓Generated artwork: BlueStreamFly · Regional illustration; not the exact location.
Good day to fish?Latest river check
Poor
Not today. Make another plan.
28
Best option: Float. A float can fit better than wading only if launches, shuttle, boat skill, wind, and local rules all check out.
See update time and confidence
Live data checkMediumHow much of the live flow, weather, and alert data came back.
Today's callLowNo structured live flow
Score calculated Aug 22, 2026, 10:23 PM MDTSources checked often
Best access methodFloat
These scores compare the risks of wading, bank fishing, and floating.
Bank / edgeNot recommended
This report does not recommend bank fishing on this reach.
Float · Best fit22/100
A float can fit better than wading only if launches, shuttle, boat skill, wind, and local rules all check out.
Your plan
Today's North St. Vrain plan.
The North St. Vrain below Button Rock is most useful when you treat it as a walk-in creek with clear access boundaries, pressure-aware presentations, and a backup option if the preserve is busy or the water is running too hard.
- Check first
- Use RiverReports for quick flow context, then match the day to Button Rock Preserve access rules and the forecast.
- Try
- Fish the first good-looking water you can reach legally because the creek near the entrance can be as useful as farther walk-in sections.
- Leave when
- Skip when the preserve lot is full, summer heat is building, or the creek is too pushy to fish from safe edge positions.
Live river check
What the river is doing
Check the latest flow and weather before you go. A quick change can make the river harder or less safe to fish.
Showing the latest stored river check while current readings load.
- Flow
- —
- Live flow is not available here.
- Air now
- 66°F
Current NWS forecast period
- Next 24h high
- 83.0°F
NWS air forecast near
- Rain chance
- 16%
For this forecast period
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
Slight Chance Showers And Thunderstorms
Slight Chance Showers And Thunderstorms
- Wind
- 3 mph
- Weather checked
RiverReports chart
Recent water trend
RiverReports gauge
BlueStreamFly cannot read the latest value from this image. Check the chart on RiverReports Opens in a new tab.
More forecast and source details
National Weather Service
North St. Vrain below Button Rock forecast point
The National Weather Service forecast is temporarily unavailable.
Live data
Where these readings come from
RiverReports gauge: North St. Vrain below Button Rock Reservoir
How to fish it
How to fish North St. Vrain today.
Late spring after runoff begins settling, summer mornings, and early fall are usually the best planning windows. Preserve crowding and exposed sunny afternoons can narrow the useful fishing window faster than the map suggests.
Low clear water
Use fine tippet, stay low, and fish smaller dries or light droppers along seams and banks.
Moderate stable flow
Best all-around condition for dry-dropper fishing and short nymph drifts.
High or pushy flow
Treat the creek as a bank-first scouting day or move to a safer backup if footing disappears.
Hot sunny afternoons
Fish early, monitor temperature, and shorten handling on pressured Front Range trout water.
Fishing words used on this page
- 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.
- Presentation
- Presentation means how you cast and move the fly so it looks natural to a fish.
- 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
Best mode nowHurts
Float: A float can fit better than wading only if launches, shuttle, boat skill, wind, and local rules all check out.
FlowUse caution
RiverReports is linked for the flow chart, but this page does not have a structured live flow value the score can read automatically. Treat the rating as conservative and open the chart before committing.
HeatUse caution
The current NWS air forecast is about 66F, and the next 24-hour high reaches about 83F. This is an air forecast, not a water-temperature reading. Fish early and check the river with a stream thermometer.
Short-term weatherUse caution
The forecast has storm or heavy-precipitation risk, so timing and access matter more than the score alone.
SeasonHelps
Summer: Primary season for early dries, caddis, terrestrials, and quick morning sessions.
Trip notes
Trip notes
Check these before you choose a reach.
Stable clear flows that leave seams and bank pockets readable without forcing aggressive crossings.
Skip when the preserve lot is full, summer heat is building, or the creek is too pushy to fish from safe edge positions.
Get there early, fish creek water near the entrance first, decide whether the walk farther in is earning value, and keep Big Thompson or Boulder Creek ready as backups.
Big Thompson, Cache La Poudre, or Boulder Creek are better pivots when Button Rock access, heat, or crowds narrow the day.
What to try
North St. Vrain flies through the year.
Match the time of year, then let rising fish and current speed guide the next change.
SeasonWhat to look forFlies to try
Spring
What to look forMidges, BWOs, and caddis
SummerCurrent
What to look forCaddis, PMDs, yellow sallies, and ants
Late summerCurrent
What to look forTerrestrials and evening caddis
Fall
What to look forBWOs and midges
Each fly name opens its matching Fly Box guide.
Access and safety
North St. Vrain access and rules.
Use these places as starting points. Open the access link below and check posted signs before you park or enter. A Colorado fishing license is required, and the City of Longmont notes that Ralph Price Reservoir also requires a separate special permit with its own season and tackle rules. Review both the Colorado brochure and the preserve rules before you fish.
Button Rock Preserve entrance and fishing pier
Best official starting point for creek access and preserve orientation.
Longmont Reservoir side of the preserve
Useful for nearby walk-in water and mixed preserve scouting close to the entrance.
Ralph Price Reservoir approach
A two-mile hike and a separate permit context if you choose the reservoir instead of the creek.
Button Rock is walk-in only beyond the gate, and the parking lot can close when it fills.
Creek fishing and Ralph Price Reservoir fishing are not the same plan. The reservoir has a separate permit structure and season.
Preserve closures and habitat-protection areas matter as much as the flow chart when choosing how far to walk.
River sources
Official North St. Vrain sources.
Official agencies and primary river operators come first. Secondary tools are labeled so you know what carries the most weight.
How this report was checked
How this report was checked
Reviewed byBlueStreamFly River Review Team
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.
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.
See all 7 checked sources
Rules and closures
Check what is allowed, where the rule applies, and whether the river is open.
What this source covers
Open the current rules and check the river section, season, and special limits.
What this source covers
Open the current rules and check the river section, season, and special limits.
What this source covers
Open the current rules and check the river section, season, and special limits.
Flow and weather
Check the latest river reading and forecast before you leave.
What this source covers
Open this page and check the latest safety advice before your trip.
What this source covers
Open this river reading to check the latest level, flow, and update time.
Access and land
Check public entry points, land rules, and seasonal access changes.
What this source covers
Open the land or access page, then check signs before you park or enter.
What this source covers
Open the land or access page, then check signs before you park or enter.
Quick answers
Quick North St. Vrain answers.
Do I need a special permit to fish the creek?
For the creek, start with a valid Colorado fishing license. The separate special permit applies to Ralph Price Reservoir inside Button Rock Preserve.
Is the best fishing far inside the preserve?
Not always. Water close to the entrance can fish well, especially when you can work it quietly before foot traffic builds.
What is the biggest planning mistake here?
Mixing up preserve access rules, reservoir permit rules, and creek strategy. Sort those out before you choose flies.