An easy start can hide a harder return
A shaded start or downhill opening can be misleading if the return requires climbing during a warmer period. The score represents one forecast point and hour, not the energy needed for the whole walk. Check the route profile and forecast across the outing rather than choosing the best-looking hour.
Park authorities can provide route-specific warnings that a generic weather model cannot. The Grand Canyon’s Hike Smart information is an example of why water availability, shade and trail conditions belong beside the forecast. Apply the relevant local authority’s information to your actual destination.
Why two hikers can make different plans
Pack weight, pace, familiarity with the route and personal circumstances are outside the scorer. A favourable model band is not permission to ignore them. A shorter shaded route with a clear exit can solve a planning problem that changing equipment alone cannot.
Use the explorer to understand the arithmetic, including how heat combines with strong gusts or rain. Do not read its precise boundary as a biological boundary. Conditions do not become harmless merely because a forecast is one degree below a deduction.
Worked examples from the existing scorer
These complete hypothetical hours run through the same scoring functions used by the live tool. They are not observations or forecasts. The displayed effective score includes any cap.
| Example | Effective score | Verdict | Model reasons |
|---|---|---|---|
| Feels-like 26°C | 90/100 | GO | warm |
| Feels-like 29°C | 75/100 | GO | very hot |
| Heat with exposed gusts | 40/100 | NO-GO | gusty on exposed trails; dangerous heat · MAYBE cap |
Exact example inputs and units
temp and feels: °C; wind and gust: km/h; precipitation: mm/h; visibility: m; rain probability, cloud and humidity: %. Weather code is WMO; UV is an index. Pressure, where shown, is context in hPa and does not affect this scorer.
[
{
"example": "Feels-like 26°C",
"inputs": {
"temp": 24,
"feels": 26,
"precip": 0,
"pop": 0,
"wind": 10,
"gust": 15,
"vis": 20000,
"code": 0,
"cloud": 10,
"humidity": 60,
"uv": 0,
"pressure": 1010
}
},
{
"example": "Feels-like 29°C",
"inputs": {
"temp": 27,
"feels": 29,
"precip": 0,
"pop": 0,
"wind": 10,
"gust": 15,
"vis": 20000,
"code": 0,
"cloud": 10,
"humidity": 60,
"uv": 0,
"pressure": 1010
}
},
{
"example": "Heat with exposed gusts",
"inputs": {
"temp": 31,
"feels": 33,
"precip": 0,
"pop": 0,
"wind": 10,
"gust": 45,
"vis": 20000,
"code": 0,
"cloud": 10,
"humidity": 60,
"uv": 0,
"pressure": 1010
}
}
]Planning bands and the limits of the number
The existing model starts at 100, subtracts its condition penalties and applies critical caps. GO is 70–100, MAYBE 45–69 and NO-GO 0–44. A MAYBE cap limits the effective score to 64, and a NO-GO cap to 40. These are application suitability bands, not certified safe operating limits.
Rain branches are alternatives: matching probability, intensity and weather-code triggers do not mean adding the same rain penalty repeatedly. Separate factors can combine. A cap prevents benign temperature or dry weather from cancelling a critical flagged condition. Use the reasons beside the result to understand what changed.
The model requires complete numeric weather inputs. Missing visibility, rain probability or another required value returns Insufficient data; it is never filled with an invented favourable value. Local warnings, closures, equipment instructions and actual observations can change your decision even when the model returns GO.
Read the full hiking methodology and thresholds. The model and these examples were cross-checked on 18 October 2026. No physical field-test or safety certification is claimed.
Equipment and an alternative plan
Select a cooler time or a less exposed route, check water access and identify turn-back points. Follow park heat restrictions and official advice. If the route depends on an optimistic forecast or a water source you have not verified, choose a simpler alternative.
Questions about Too hot to hike? Exposure, ascent and the return route
Does 33°C automatically score NO-GO?
In the hiking model the heat input alone loses 45 points and caps at MAYBE; the app is not certifying that exposure is safe.
Can the forecast see shade on the trail?
No. Route shade and terrain are not model inputs.
Does the daily maximum describe the summit?
No. A selected point is not the whole elevation profile.
Sources and limits
The numeric application bands come from the existing GoNoGo scorer and methodology. External guidance is linked for its stated context; it is not presented as endorsement of this model.
Live forecast data is supplied by Open-Meteo. An illustrative model output is different from a live forecast, and a forecast is different from a local observation.