Next to the mean wind at your flying height, Altiwind shows estimated gusts: the short bursts of stronger wind your drone has to fight. Weather models forecast gusts near the ground, not at 120 m, so Altiwind carries the 10 m gustiness up to your altitude. We always call the result "estimated gusts", because that is exactly what they are.
Why gusts matter more than the mean
A steady wind is predictable. Your drone leans into it, holds position and you can plan the flight back. A gust is a sudden jump in speed. The drone has to tilt further and draw more power to hold its place, and it may drift before it catches up.
The maker's wind resistance figure is roughly the most the drone can hold against. A mean wind well under that can still bring gusts over it, and those are the moments when a drone gets pushed backwards or struggles home on a low battery. That's why gusts have their own check in the go/no-go score. More in the guide on gusts vs sustained wind.
How the estimate works
- Gust excess at 10 m. Altiwind takes the model's forecast gust at 10 m and subtracts the forecast mean wind at 10 m. A gust of 32 km/h on a mean of 20 km/h is an excess of 12 km/h.
- Add it to the wind at altitude. The excess on top of the wind at your flying height gives the estimated gust there.
- Keep a floor. The estimate is never less than 1.2× the wind at that height, because the air is rarely perfectly smooth, and never less than the 10 m gust, because your drone climbs through that layer on the way up and down.
Why add the excess rather than multiply by the gust ratio? Near the ground, friction slows the mean wind much more than it shrinks the gusts riding on it. The size of a gust above the mean changes far less with height than the mean wind does, so the 10 m ratio (gust ÷ mean) is inflated by the slow mean right at the surface. Multiplying the stronger wind aloft by that ratio would roughly double it on many breezy days.
Example
The forecast for 10 m says a mean of 20 km/h with gusts to 32 km/h, an excess of 12 km/h. The wind at 120 m is 27 km/h (16.8 mph, 14.6 kn).
Estimated gust at 120 m: 27 + 12 = 39 km/h (24.2 mph, 21.1 kn).
Now take a drone rated for 10.7 m/s (38.5 km/h, 23.9 mph, 20.8 kn). The mean wind is 70% of that, which is "Marginal". The estimated gust is 101%, which is "Outside your limits". The gust check is the worst one, so the hour shows "Outside your limits", even though the mean wind alone looks manageable.
A smooth-air case shows why the floor is there: a mean of 30 km/h gusting 32 km/h is an excess of only 2 km/h. With 40 km/h at 120 m that would give 42 km/h, so Altiwind uses the floor of 1.2 × 40 = 48 km/h.
Why we label them "estimated"
- No model forecasts gusts at 120 m directly. The gust number comes from 10 m and is carried up.
- Gusts come from turbulence the model can't see. Tree lines, buildings, ridges and passing showers all make their own gusts, on scales far smaller than a model grid cell.
- Gustiness changes with height. Turbulence from obstacles near the ground often eases higher up, while gusts under a shower cloud can be stronger aloft.
So read the estimated gust as a guide and leave yourself a margin. The verified badge shows how the forecast's 10 m wind and gusts have compared with the nearest airport's reports.
What you get
Estimated gusts at your chosen altitude for today and the next 24 hours, with a gust reason chip in the go/no-go score.
FAQ
Why is the gust at 120 m higher than in my weather app?
Your weather app shows gusts at 10 m. The wind at 120 m is usually stronger, and Altiwind adds the same gust excess (gust minus mean) on top of that stronger wind.
Why not just use the model's 10 m gust?
Because your drone isn't at 10 m. A 10 m gust figure would usually understate what the drone meets at 60 or 120 m.
Can the estimate be wrong?
Yes. It is a reasonable estimate, not a measurement. Local terrain, buildings and showers can make gusts stronger or weaker than the estimate, which is why the go/no-go score keeps a margin below your drone's rating.