How the Lago di Santa Croce wind forecast works
What it does
Lake Wind Watch answers one question: is it worth going to Lago di Santa Croce today or tomorrow, and at what time.
Every hour an engine reads several weather models, identifies the expected wind regime and turns it into an hourly window with mean speed and gusts in knots.
Local station data tells you what is happening right now and, every night, checks how close yesterday's forecast actually was.
The regimes
- R0 — Calm: no mechanism active, wind below the useful threshold.
- R1 — Thermal: the S/SW breeze that climbs through the Fadalto saddle on sunny days.
- R2 — Bora from NE: cold outbreak with a strong gradient towards the Adriatic; the lake station cannot see it, so it is not verifiable.
- R3 — Synoptic NW: downslope flow from the Alps; also not verifiable with the lake station alone.
- R4 — Disturbed: rain or persistent low cloud that kills the thermal.
- R5 — Thunderstorm danger: convective instability; always a hazard, never an opportunity.
- R6 — Synoptic S/SW: strong southerly flow aloft, which can bring wind even at night or in the rain.
Why the wind comes from Fadalto
On sunny days the Veneto plain heats up far faster than the lake water.
Warm air over the plain is lighter and rises, leaving room for air drawn in from the south.
That flow runs up the Val Lapisina and squeezes through the narrow Fadalto saddle, where it channels and accelerates.
The lake stays cool and smooth: the air spills over it and becomes the S/SW wind you feel on the beach from early afternoon.
At night the mechanism reverses and cold air drains downhill — that is the drainage flow measured at the Lago Morto station.
Where the numbers come from
Forecasts come from several Open-Meteo models: ICON-D2, AROME HD, ICON-EU and ECMWF IFS.
We do not use an ensemble: the uncertainty band and the confidence come from the spread between these models, so with few models available the band is less reliable.
Observations come from two local stations, the Davis at Santa Croce and the one at Lago Morto, with history from 2022 to 2026.
Thanks to the station owners, who make their data public.
Where the parameters come from
Every threshold and coefficient in the engine carries a tag saying where it comes from, so no number is left without a source.
LETT = from scientific literature. LOC = from local sources and riders' observations. DATI = measured at the Santa Croce station. IPO = assumption still to be calibrated. CAL = value adjusted by automatic calibration on verified data.
Limits
This is not an official bulletin and does not replace warnings from the authorities.
Thunderstorms are always a hazard, never a window to use: with convective risk a day is never marked as sailable.
The reference anemometer reads less than the real wind over the water: a day averaging 7 kt at the station can be excellent for kiting and sailing. The verdict thresholds are tuned on riders' judgements, not on numbers alone.
The reference station only sees the southern sector well: NE and NW regimes cannot be verified with our data.
Always check conditions on site before going on the water.
Whoever publishes this data takes no responsibility for how it is used.
This is not an official bulletin. Always check on site.