Reading a wind forecast for kitesurf lessons
A forecast is a number a computer produced for a square several kilometres wide. An observation is what an instrument, or a person, recorded at one place and one time. Most of the confusion around "the forecast was wrong" comes from treating the first as if it were the second. This guide explains the four things on a wind forecast that decide whether a lesson happens — average, gust, direction and time — what a model can and cannot know about a beach, and how schools actually use it.
Forecast is not observation
A computed estimate for a future or current hour, for a grid cell. Open-Meteo, ECMWF, GFS, NOAA NWS are models. Everything on KiteSchool.app's wind cards is this.
A reading from an instrument at a fixed point and time: a buoy, an airport anemometer, a school's own wind meter on the beach.
A dated report from a person on the spot — the instructor who says "20 knots and gusty at the lagoon at 14:00". Not a measurement, but real information the model does not have.
How much evidence supports a number, not a promise it is safe. Two models agreeing with a nearby buoy is high confidence; one model with no station within 50 km is low.
KiteSchool.app labels every wind number as a forecast, names the model, and shows both the model's valid time and when we fetched it. When a spot has no value, the card says the forecast is unavailable — it does not show a "typical" number, because a typical number scored as ideal is a fabricated condition.
The four numbers that matter for a lesson
Average speed
Usually the 10-minute mean at 10 m height, in knots. Beginners are commonly taught in roughly 12–20 knots of steady wind with a suitable kite; the exact band depends on the student's weight, the kites the school owns and the spot. Below about 10 knots most beginners cannot generate power; above the mid-20s the margin for mistakes disappears.
Gust
The peak inside the averaging window. A forecast of 15 gusting 17 is a different day from 15 gusting 25: the second one is what pulls a beginner off their feet during a water start. As a rule schools care about the gust factor (gust ÷ average). Above roughly 1.4 the wind is called gusty and many schools move beginners to a more sheltered spot or a later hour. If a forecast shows no gust value, it is because the model did not report one — KiteSchool.app then shows none rather than inventing one.
Direction
Where the wind comes from. Relative to the beach: side-shore and side-onshore are the teaching directions — you can be blown back to the beach and still ride along it. Onshore pushes you and the kite onto the sand and any obstacle behind it. Offshore takes you out to sea; most schools will not teach beginners in it and many will not launch at all. The same 15 knots is a lesson in one direction and a rescue in another.
Time — two of them
Every forecast value is valid for an hour, and was produced at a time. A value for 15:00 pulled at 08:00 is a plan; the same hour pulled at 14:30 is close to a condition. On KiteSchool.app the card says "as of 15:00 local" for the model's valid hour and the row header says when we last fetched. Cards not refreshed in 90 minutes grey out and say so.
Where forecasts go wrong near the coast
A global model resolves the atmosphere on cells several kilometres across and at fixed heights. A beach is not a cell. The predictable failures:
- Sea breeze. On a sunny coast the land heats, air rises, and an onshore breeze builds in the early afternoon that the morning run of a coarse model under-calls by several knots. Schools in Ceará plan lagoon sessions around the afternoon strengthening for exactly this reason.
- Headlands, dunes and jetties. Wind accelerates around a point and lulls behind a dune line. A model reports the cell average; the lagoon two kilometres inland can be steadier than the beach at the same hour, which is why some spots teach on a lagoon at all.
- Gust structure. Models estimate gusts statistically. A squall line or a thermal cell gives real gusts the forecast never shows.
- Timing. A front that arrives two hours late looks, on the beach, like a wrong forecast. It was a right forecast with a timing error — which is why a school checks the current value again before rigging.
A worked example: during Hurricane Marie's swell in September 2026 an AYON field note recorded a wave model giving eight Newport Beach spots identical values while the real ocean ranged from flat to well overhead three kilometres apart. Wind has the same resolution gap. The fix is not a better model; it is a person on the spot and a record of how that spot behaves.
How a school turns a forecast into a lesson plan
| Forecast reads | What an experienced school does |
|---|---|
| 12–18 kt, gusts within ~1.3×, side-onshore, steady across the afternoon | Books beginner water sessions. Chooses kite size for the student's weight; keeps a smaller kite rigged in case the sea breeze builds. |
| Same average, gusts 1.5× or more | Moves beginners to the sheltered option (a lagoon, the lee of a point) or to a calmer hour; keeps intermediates on the beach with a size down. |
| Offshore component | No beginner water time. Some schools will not launch anyone; those that do keep a boat on the water. |
| Below ~10 kt all day | Theory, kite control on land, or reschedule under the no-wind policy you agreed when booking. |
| Forecast unavailable or stale | Calls the beach. A missing number is missing information, not a calm day. |
The forecast decides whether to plan. The instructor on the sand, with the current value and their own eyes, decides whether to launch. Any school that inverts that order is one to be careful with — see the rescue questions in how to choose a kite school.
Frequently asked questions
Is the wind on KiteSchool.app measured or forecast?
Forecast, from the Open-Meteo weather model, labelled with the model's valid time and our fetch time. It is not a beach anemometer. Where the model has no value, the card says so instead of showing a typical number.
What is a good wind speed for a beginner lesson?
Roughly 12–20 knots of steady wind with the right kite size, depending on weight, kites available and the spot. Gusty wind at the same average is harder and less safe — read the gust, not just the average.
Why does the forecast say 15 knots but the beach feels different?
The number is for a model cell several kilometres wide, not for your beach. Headlands, dunes and the sea breeze are invisible to it. Schools plan around their spot's known biases.
How old can a forecast be and still be useful?
Check the valid hour and the fetch time. Valid for now and fetched in the last hour is current; fetched this morning for this afternoon is a plan. KiteSchool.app greys out cards not refreshed in 90 minutes.
See the forecast for a spot with schools on it
The discover page shows the Open-Meteo forecast for each spot that has a listed school, labelled with its time and source, next to the schools that teach there — Cumbuco, Jericoacoara & Preá and Fortaleza have their own guides.
Open wind by spot