How We Score Trails

Every trail gets a 1–100 score based on live conditions. Here's exactly how it works.

The Score at a Glance

Each trail score is a weighted composite of four real-time factors: weather conditions, air quality, fire proximity, and trail access status. The score updates every 20 minutes via automated pipelines that pull directly from government and scientific data sources.

The goal is simple: one number that tells you whether today is a good day to hit a trail.

Score Tiers

85–100
Great day to go
Ideal conditions across the board. Comfortable temps, clean air, low wind, no fire concerns.
70–84
Good conditions
Solid conditions with minor factors to watch. Still a great day for experienced hikers.
50–69
Use caution
One or more factors are elevated. Check details before heading out and bring extra gear.
30–49
Conditions poor
Significant weather, air quality, or fire concerns. Consider a different trail or day.
Below 30
Stay home
Multiple factors are dangerous. We'll suggest alternative trails where conditions are better.

Scoring Factors

The 100-point score breaks down into four weighted categories:

Weather Conditions 40 points
Based on current temperature, wind speed, and rain probability.
  • Full 40 pts: 50–75°F, wind under 15 mph, rain chance under 10%
  • 28 pts: 40–85°F, wind under 25 mph, rain under 30%
  • 10 pts: 35–95°F, wind under 35 mph, rain under 60%
  • 0 pts: Conditions outside all thresholds
Air Quality Index (AQI) 30 points
Based on real-time AQI readings from EPA monitoring stations.
  • Full 30 pts: AQI 0–50 (Good)
  • 20 pts: AQI 51–100 (Moderate)
  • 10 pts: AQI 101–150 (Unhealthy for Sensitive Groups)
  • 0 pts: AQI above 150
Fire Proximity 20 points
Based on satellite-detected fire hotspots within range of the trailhead. More nearby fires and closer proximity reduce the score. Data comes from NASA's Fire Information for Resource Management System (FIRMS), which detects thermal anomalies from multiple satellites updated throughout the day.
Trail Access Status 10 points
Whether the trail is open or closed due to seasonal restrictions, construction, or hazards. Currently assumes open status while we integrate real-time closure feeds from land management agencies.

Data Sources

All scoring data comes from trusted government and scientific sources:

Weather Open-Meteo — hourly and 7-day forecasts for each trailhead's exact coordinates
Air Quality AirNow (EPA) — real-time AQI from the nearest monitoring station, with Open-Meteo fallback
Fire Data NASA FIRMS — MODIS and VIIRS satellite fire detections within proximity of each trail
River Levels USGS — stream gauge data for trails with water crossings

Update Frequency

Our data pipeline runs every 20 minutes via GitHub Actions. Each run fetches fresh weather readings, AQI data, and fire satellite passes, recalculates every trail score, and publishes updated conditions to the site. The timestamp on each trail page shows exactly when its data was last refreshed.

The 3-day forecast on each trail page is also regenerated on every pipeline run, so forecast data is never more than 20 minutes old.

Frequently Asked Questions

How often are trail scores updated?
Every 20 minutes. Our automated pipeline runs around the clock, pulling fresh data from Open-Meteo, AirNow, and NASA FIRMS with each cycle.
What does a score of 80–100 mean?
Great conditions. Temperature is comfortable (50–75°F), wind is light, rain chance is minimal, AQI is good, and there are no nearby fire concerns. It's a great day to hit the trail.
What does a score below 50 mean?
Conditions are poor due to one or more factors: extreme heat or cold, high winds, significant rain probability, poor air quality, or nearby wildfire activity. We recommend checking alternative trails that may have higher scores.
Where does the data come from?
All data comes from government and scientific sources: Open-Meteo for weather, the EPA's AirNow network for air quality, NASA FIRMS satellites for fire detection, and USGS stream gauges for river levels.
Can I trust the score for trip planning?
The score is a helpful starting point based on real-time data, but it shouldn't be your only source. Always check local ranger stations, permit requirements, and current closures before heading out. The score doesn't account for trail-specific hazards like rockfall, snow coverage, or permit availability.
Why does the same trail score differently at different times of day?
Because conditions change throughout the day. Temperature, wind, and AQI all fluctuate. Morning scores might be higher when temperatures are moderate, while afternoon scores might drop if wind picks up or heat increases.