2
Grafham Water
United Kingdom68
Great
Today's podium
Weather data from Open-Meteo, refreshed every 3 hours.
How the score works
Wind viability gates the whole score: sustained wind is matched to each boat category's ideal range and multiplies everything else, so a becalmed day scores near zero. Gust stability and visibility also multiply, while sea state, precipitation, storm risk, wind consistency, and pressure trend form a weighted composite. The day's score is 70% the best 4-hour window across racing hours (09:00-18:00) plus 30% the racing-hours average. Toggle between Club Dinghy and High Performance to see how the wind quality curve shifts.
Wind QualityGate
The make-or-break factor. Sustained wind multiplies the whole score, so no wind means no score. Club dinghies peak at 14-16 knots; high performance boats at 18-20 knots.
Gust FactorMultiplier
Unstable wind multiplies the score down. Gusting double the sustained wind is postponement territory, with the penalty amplified at higher wind speeds.
Sea State32%
Wave height curve centred on 0.2-0.3m. Steep swell and wind-against-tide both penalise. Inland venues score near-perfect by default.
Precipitation20%
Rain rate curve. Thunderstorms suppress the score to near zero as sailing must stop.
Storm Risk20%
CAPE and lifted index thresholds. Any active thunderstorm forces the score to zero for safety.
Wind Consistency18%
Circular standard deviation of wind direction. Shifty winds penalised, with offshore exposure amplifying the effect.
Pressure Trend10%
Barometric pressure change per hour. Rising or stable pressure scores well; rapid drops signal deteriorating conditions.
VisibilityMultiplier
Fog has real bite: visibility multiplies the score rather than nudging it. Below 500m across the window triggers suppression.
Thermal ExposureNot scored
Shown for context but excluded from the score. Temperature would create permanent geographic bias, and sailors dress for the climate.
Frequently asked questions
How often is this updated?
Every 3 hours when the conditions cron runs. We pull fresh wind, wave, and weather data for every venue and recalculate both boat category scores.
What is the difference between Club Dinghy and High Performance?
Club Dinghy scoring is optimised for boats like the Laser, RS200, and Wayfarer. These peak at 14-16 knots and are penalised more heavily by strong gusts. High Performance scoring suits boats like the 49er, Moth, and RS800. These want 18-20 knots and tolerate a wider wind range.
How is the score calculated?
Wind viability gates everything: sustained wind is matched to each boat category's ideal range and multiplies the rest of the score, so a becalmed day scores near zero however sunny it is. Gust stability and visibility also multiply, while sea state, precipitation, storm risk, wind consistency, and pressure trend form a weighted composite. The day's score is 70% the best 4-hour window across racing hours (09:00-18:00) plus 30% the racing-hours average.
What does Becalmed mean?
Becalmed is the lowest label. Below roughly 4 knots the wind viability gate takes the score to 2 or less, because there is simply no sailing to be had, however pleasant the weather.
Why are some scores suppressed to zero?
Safety. Persistent thunderstorms, sustained winds above 40 knots, gusts above 50 knots, or visibility below 500m all trigger automatic suppression. The suppression reason is shown on the row.
How are inland and coastal venues compared?
Inland venues skip the sea state sub-factor and score near-perfect there. Coastal venues face wave penalties, swell steepness checks, and wind-against-tide effects. The leaderboard is intentionally global, so both types compete on the same scale.
Where does the data come from?
Open-Meteo Weather API for wind, temperature, pressure, and visibility. Open-Meteo Marine API for wave and swell data at coastal venues. The same underlying models power many sailing forecast apps.
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