Plan for slowing down as well as warming up
Running can make a cool start feel comfortable, but a delay, injury or long walk home changes the situation. The weather score does not know the insulation you carry or whether you will still be moving at the planned pace. Choose a route whose exit remains practical if the session becomes a walk.
The feels-like input is a model value, not a personal skin-temperature reading. Wind exposure and wetness can differ along the route. Use the hourly forecast and local observations instead of treating the daily low as the conditions everywhere.
Surface ice is a separate question
The model recognises wintry weather codes, but it does not inspect every pavement, bridge or shaded section. A path can retain ice after the air warms. Suitable footwear cannot guarantee grip on an unverified surface, and a GO does not certify that a route is clear.
An earlier return, a familiar cleared route or an indoor session can address uncertainties that the scorer cannot measure. Keep the training objective flexible. The boundary examples explain the existing product rules; they are not a challenge to run just above the next penalty.
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 −2°C | 100/100 | GO | No model penalties |
| Feels-like −3°C | 85/100 | GO | very cold |
| Wintry code 71 | 30/100 | NO-GO | ice underfoot; very cold · NOGO 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 −2°C",
"inputs": {
"temp": 0,
"feels": -2,
"precip": 0,
"pop": 0,
"wind": 10,
"gust": 15,
"vis": 20000,
"code": 0,
"cloud": 10,
"humidity": 60,
"uv": 0,
"pressure": 1010
}
},
{
"example": "Feels-like −3°C",
"inputs": {
"temp": -1,
"feels": -3,
"precip": 0,
"pop": 0,
"wind": 10,
"gust": 15,
"vis": 20000,
"code": 0,
"cloud": 10,
"humidity": 60,
"uv": 0,
"pressure": 1010
}
},
{
"example": "Wintry code 71",
"inputs": {
"temp": -1,
"feels": -3,
"precip": 0,
"pop": 0,
"wind": 10,
"gust": 15,
"vis": 20000,
"code": 71,
"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 running 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
Adjust layers for both moving and stopping, keep a practical route back and check the surface in person. Follow local cold-weather advice. If ice or exposure makes the route uncertain, use a cleared alternative or move the session indoors rather than forcing the original distance.
Questions about Too cold to run? Wind chill, ice and the trip home
Does cold alone always produce NO-GO?
No. The model’s cold deductions are different from its snow, storm and wind caps.
Does feels-like above zero mean no ice?
No. Surface conditions are not measured.
Can the app know whether my clothing is enough?
No. Clothing and personal exposure are outside the scorer.
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.