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Methodology

How Go Score Works

Go Score fuses seven independent condition dimensions into one number — 0 to 100 — so you can answer the first question of any trip: Is it worth going?

What Go Score measures

Go Score is a daily trail conditions fusion score — a single number from 0 to 100 that tells you how favorable the current conditions are for hiking, backpacking, or peak-bagging on a specific trail. It is not a safety rating, a difficulty grade, or a prediction of your experience. It is a conditions readout, nothing more.

Think of it like a weather forecast for the trail: it tells you what the environment is doing right now, translated into a simple scale. On a clear day with good trail conditions, a popular trailhead scores in the high 70s or 80s. After a storm, during wildfire season, or when an avalanche warning is in effect, the same trail can drop to 20 or lower — or to 0 if a hard stop is triggered.

Go Score covers 300+ trails across all 8 Mountain West states. Colorado has the deepest coverage (58 fourteeners plus popular 13ers and trailheads). Montana, Wyoming, Idaho, Utah, Nevada, New Mexico, and Arizona are all in the system. The scoring inputs are consistent across states; the data sources and regional hazard rules vary by state.

What Go Score is NOT

Go Score does not account for your personal fitness, navigation ability, time available, group size, or gear readiness. It does not replace trip planning, emergency communication, or Leave No Trace ethics. It does not predict snow stability or river crossing safety — those require human judgment and, in some cases, professional avalanche or river safety training.

The seven inputs

Go Score evaluates seven independent dimensions of trail conditions. No weights are published — not because the algorithm is secret, but because context matters more than the number. A 15-point weather penalty means something different in January than in July.

# Input What it evaluates
1 Weather Forecast Open-Meteo · NWS grid points Temperature range, precipitation probability, wind speed, visibility, and storm timing for the trailhead elevation. Elevation bands (trailhead, treeline, summit) are assessed independently. Open-Meteo provides hourly resolution; NWS WFO grid data gives authoritative point-source forecasts for each trail.
2 Avalanche Danger CAIC · GNFAC · WCMAC · FAC Current avalanche danger level for the trail's CAIC/GNFAC/WCMAC zone. Colorado uses CAIC zone forecasts; Montana uses GNFAC (Glacier area) and WCMAC (West Central). Danger levels 1–5 map directly to score impact. Danger 3 (Considerable) reduces the score; Danger 4–5 triggers a hard stop.
3 Trail Community Reports PeakScout trail report submissions User-submitted trail condition reports from the past 7 days. Reports include snow depth, mud level, stream crossing status, and ice conditions. Reports older than 72 hours decay in influence. Reports below treeline (trailhead to 10,500 ft) and above treeline are assessed separately. Auto-hidden reports (3+ flags) are excluded.
4 Road Access Status CDOT · USFS ArcGIS · BLM · NPS Current status of the access road to the trailhead, sourced from CDOT for Colorado, USFS ArcGIS for national forest roads, BLM, NPS, and MT DNRC for Montana. An officially closed road sets a hard stop (score = 0). A snow-closure advisory reduces the score based on seasonal context.
5 Wildlife & Seasonal Closures USFS · NPS · BLM · ArcGIS Active wildlife habitat closures (bighorn sheep lambing, raptor nesting, grizzly core areas in MT/WY/ID), seasonal closures (mud season, avalanche terrain), and fire restrictions that affect the trail or surrounding area. A verified official seasonal closure triggers a hard stop.
6 Wildfire Smoke Quality AirNow EPA · Open-Meteo AQI fallback Current air quality index (AQI) at the trail location, sourced from AirNow EPA as primary (requires API key) with Open-Meteo as fallback. Elevation factor: trails above 8,000 ft receive a +10% penalty amplification per 1,000 ft above that threshold. AQI above 150 at elevation triggers a hard stop. AQI above 100 reduces the score proportionally. Source attribution: "Wildfire smoke sourced from AirNow/EPA."
7 Crowding & Parking Pressure Day-of-week · Trail popularity tier · US federal holidays A signed modifier (−8 to +3 pts) reflecting expected trailhead congestion. High-traffic trails on holiday weekends (Memorial Day, July 4th, Labor Day, Thanksgiving, Christmas) receive the steepest penalty. Standard weekend visits to popular trails carry a moderate penalty — trailhead parking fills by 8am and the experience degrades accordingly. Midweek visits to lower-traffic trails earn a small bonus. This signal captures a real-world trip outcome factor: a trail with perfect weather but an overflowing parking lot at 7am is not a "Go" in the same way as an uncrowded midweek visit.

Score interpretation guide

Use this guide to translate the score into a practical decision frame. Remember: the score describes conditions, not your plan. A trail at 65 might be a perfect hike — or it might be the wrong trail for today's weather window.

80–100
Go
Conditions stacking in your favor. Clear forecast, no closures, manageable trail conditions. Standard day-hike preparation applies.
60–79
Caution
One or more signals is degraded. May be fine for experienced hikers; check the specific signal before committing.
40–59
Check Twice
Multiple signals degraded. Reassess your route, turn-around time, and weather window before heading out.
20–39
Risky
Significant hazards active. Consider an alternative or defer the trip. Hard stops likely if avalanche or fire perimeters are involved.
0
Don't Go
At least one hard stop is active. Check the trail card for the specific reason. Do not proceed without verifying with the managing agency.

Hard stops — when the score is zero

Hard stops are conditions so hazardous that no other favorable signal can compensate. When a hard stop is active, the Go Score reads 0 and displays "Don't Go" with the specific reason. These are not advisory — they reflect verified official closures or dangerous environment states.

Conditions that cap Go Score at 0
  • Access road officially closed by CDOT, USFS, NPS, BLM, or MT DNRC
  • Trail has an active seasonal, wildlife, or emergency closure from a land management agency
  • Avalanche danger level 4 (High) or 5 (Extreme) in the trail's zone per CAIC or GNFAC
  • Active wildfire perimeter within the trail boundary or within 1 mile of the trailhead (per NIFC WFIGS / InciWeb)
  • Extreme heat: ambient temperature above 107°F in AZ, NM, NV, or UT desert trail areas
  • Elevation-factored AQI above 150 — wildfire smoke making outdoor exertion dangerous regardless of other signals

When a hard stop is triggered, the trail card shows the reason in red type beneath the score. The trail remains in the system — checking back after conditions change will show an updated score. Hard stops are cleared automatically when the underlying data (road closure lifted, fire contained, avy danger reduced) is reflected in our data sources.

What the score shows — and what it hides

Transparency about the score's limitations is part of how we build trust. Here is what Go Score does and does not account for.

✓ What Go Score shows
  • Current weather conditions at trail elevation
  • Avalanche danger level for the trail's zone
  • Trail community reports from the past 7 days
  • Road access status from official sources
  • Active wildlife and seasonal closures
  • Wildfire smoke concentration (AQI)
  • State-specific hazard penalties (monsoon, grizzly, extreme heat)
  • Hard blocker alerts when a trail should not be attempted
  • When a trail score last updated (computed_at timestamp)
— What Go Score intentionally hides
  • The internal weighting formula (context-dependent, would be misleading without it)
  • Your personal fitness, experience, or acclimatization
  • Group size, trip duration, or bail-out options
  • Real-time trail conditions between report updates
  • Snow stability (requires field assessment or professional forecast)
  • Stream crossing danger (water level fluctuates hourly)
  • Your route-finding ability or navigation skills
  • Specific gear requirements for the day
  • Legal access status for private or permit-required trails

Frequently asked questions

What does Go Score actually measure?
Go Score measures how favorable the current conditions are for a given trail, combining seven independent dimensions: weather forecast, avalanche danger, trail community reports, road access status, wildlife and seasonal closures, wildfire smoke quality, and a crowding modifier based on day-of-week, holiday proximity, and trail popularity tier. Each dimension is assessed on its own merits — the final 0–100 score reflects how many of these dimensions are cooperating on any given day.
Is Go Score a safety rating?
No. Go Score is a conditions-fusion tool, not a safety guarantee. It tells you whether conditions are favorable for your outing, but it does not account for your personal fitness, experience level, gear, or route-finding ability. A trail with a Go Score of 85 is in great shape — but that says nothing about whether you should attempt it alone, in the dark, without rain gear. Always pair the Go Score with your own judgment and official agency advisories.
Why doesn’t Go Score publish its exact formula?
Because the formula would be misleading without full context. The weight each signal receives changes by season, elevation, and region. A 20-point weather penalty in January means something different than the same penalty in July. Publishing "Weather = 30%" would encourage users to reverse-engineer a score that doesn’t apply to their specific situation. Instead, we publish what we measure and how to interpret the output — the score itself is the product, not the math behind it.
How often does Go Score update?
Go Scores are recomputed hourly via automated cron job, starting 90 seconds after the server boots. Between updates, the score reflects conditions as of the last computation time, not live conditions. During rapidly changing events — a sudden storm, an avalanche warning, or a new fire perimeter — the score may lag the reality by up to 60 minutes. Check the computed_at timestamp on each trail’s score card.
What is a hard stop and how does it affect the score?
A hard stop is a condition so hazardous that we cap the Go Score at 0 regardless of how favorable all other signals are. Hard stops include: an active official road or trail closure, an avalanche danger of 4 (High) or 5 (Extreme) in the trail’s zone, wildfire within the trail boundary or 1 mile of the trailhead, extreme heat above 107°F in desert states, or AQI above 150 at elevation-factored measurement. When a hard stop is active, the score reads "Don’t Go" with the specific reason shown on the trail card.
Why does my trail show different scores on the briefing page versus the conditions page?
The briefing page shows a single blended Go Score for the broader region — a representative composite for the Front Range, not a specific trail. The conditions page shows per-trail Go Scores for each of the 300+ trails in our database, computed individually with trail-specific coordinates, elevation, and zone information. The briefing score and the trail score use the same signal sources but different reference points. Trust the trail-level score for trip planning.
Does Go Score work for states other than Colorado?
Yes. Go Score coverage includes all 8 Mountain West states: Colorado, Montana, Wyoming, Idaho, Utah, Nevada, New Mexico, and Arizona. Montana uses GNFAC avalanche data, Wyoming uses Bridger-Teton zone forecasts, and Arizona and New Mexico include monsoon season penalties. The scoring inputs are consistent across states — the data sources and regional hazard rules differ based on what agencies cover each area.
See today’s briefing → View all trail conditions →
Last updated May 22, 2026. Go Score methodology may be updated as data sources and scoring rules evolve.