Mean wind and peak gust are different inputs
The mean is a sustained summary; the gust represents a shorter peak. Do not average the two together to create a more comfortable number. In the explorer, an otherwise mild hour can become MAYBE or NO-GO because the supplied gust crosses an existing cap.
A model point is not a continuous measurement along a passage. Local shelter, exposed water and the route’s timing can change what you encounter. Rechecking the forecast is useful, but it does not turn a delayed or uncertain squall into a precisely timed event.
Prepare before conditions demand an urgent change
The score does not assess the crew’s ability to handle a sudden change, the boat’s condition or the time needed to reach shelter. Those are part of the passage decision. A short outing close to an appropriate return is different from a long exposed leg even with the same starting forecast.
Storms also impose a separate NO-GO cap. A benign average wind cannot cancel that flag, and a low rain amount is not evidence that lightning or sudden changes are absent. Do not use the explorer’s artificial combination as a forecast for the next squall.
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 |
|---|---|---|---|
| Mean 15, gusts 25 km/h | 100/100 | GO | No model penalties |
| Mean 15, gusts 45 | 64/100 | MAYBE | strong — reef down · MAYBE cap |
| Thunderstorm code | 10/100 | NO-GO | thunderstorms · 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": "Mean 15, gusts 25 km/h",
"inputs": {
"temp": 15,
"feels": 15,
"precip": 0,
"pop": 0,
"wind": 15,
"gust": 25,
"vis": 20000,
"code": 0,
"cloud": 10,
"humidity": 60,
"uv": 0,
"pressure": 1010
}
},
{
"example": "Mean 15, gusts 45",
"inputs": {
"temp": 15,
"feels": 15,
"precip": 0,
"pop": 0,
"wind": 15,
"gust": 45,
"vis": 20000,
"code": 0,
"cloud": 10,
"humidity": 60,
"uv": 0,
"pressure": 1010
}
},
{
"example": "Thunderstorm code",
"inputs": {
"temp": 15,
"feels": 15,
"precip": 0,
"pop": 0,
"wind": 15,
"gust": 25,
"vis": 20000,
"code": 95,
"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 sailing 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
Agree a plan appropriate to the vessel and crew, check warnings and keep return options realistic. Follow the boat’s guidance and qualified local advice for sail handling. If the plan depends on the peak gust not occurring, change the plan before leaving shelter.
Questions about Gusts and squalls while sailing: read beyond the average
Does the scorer use the average wind first?
For sailing it uses gusts when a gust value is supplied.
Can it time the next squall?
No. It is not a squall detection service.
Does a mild temperature offset the gust cap?
No. Favourable factors cannot remove a critical cap.
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.