Altiwind shows the forecast wind at 30, 60, 90 and 120 m (100, 200, 300 and 400 ft) above the ground, not just the 10 m figure most weather apps show. Wind usually gets stronger with height, so the number at your flying height is often well above the one you feel on the ground.
Why the 10 m number isn't enough
Weather apps report wind at 10 m, the standard height for weather station anemometers. Near the ground, grass, hedges, trees and buildings slow the air down. Higher up there is less friction and the wind is faster, and that is where your drone flies. The guide on how wind changes with height explains why.
How Altiwind works it out
From the model levels
The forecast comes from Open-Meteo, using the regional model for your area: DWD ICON-D2 in Central Europe, the UK Met Office UKV 2 km in the UK, Météo-France AROME in France, NOAA HRRR in the US and ECMWF IFS everywhere else. These models give wind at 10, 80, 120 and 180 m above ground.
For heights in between, Altiwind interpolates on a log scale (a straight line against the logarithm of height). That matches how wind usually behaves near the ground: rising quickly in the first few tens of metres, then more slowly.
Say a model gives 18 km/h at 10 m and 26 km/h at 80 m. For 30 m:
18 + (26 − 18) × ln(30/10) ÷ ln(80/10) = 18 + 8 × 0.53 ≈ 22.2 km/h
When a model only has 10 m wind: the power law
Then Altiwind uses the power law:
v(h) = v10 · (h/10)^α
Here v10 is the 10 m wind, h is your height in metres and α (alpha) describes how quickly wind grows with height. Altiwind uses α = 0.14 over open land, and 0.20–0.30 at night or over towns and forest.
A worked example
The forecast says 18 km/h (11 mph, 10 kn) at 10 m over open farmland in the afternoon, so α = 0.14. For 120 m:
- 120 ÷ 10 = 12
- 12^0.14 = e^(0.14 × ln 12) = e^(0.14 × 2.485) = e^0.348 ≈ 1.42
- 18 × 1.42 ≈ 25.5 km/h
| Height | Factor (h/10)^0.14 | Wind |
|---|---|---|
| 10 m (33 ft) | 1.00 | 18.0 km/h (11.2 mph, 9.7 kn) |
| 30 m (100 ft) | 1.17 | 21.0 km/h (13.0 mph, 11.3 kn) |
| 60 m (200 ft) | 1.29 | 23.1 km/h (14.4 mph, 12.5 kn) |
| 90 m (300 ft) | 1.36 | 24.5 km/h (15.2 mph, 13.2 kn) |
| 120 m (400 ft) | 1.42 | 25.5 km/h (15.8 mph, 13.8 kn) |
On a clear, calm evening, with α = 0.25, the same 18 km/h becomes 18 × 12^0.25 ≈ 18 × 1.86 ≈ 33.5 km/h (20.8 mph, 18.1 kn) at 120 m. That is why an evening that feels still in the car park can be properly breezy at the top of your climb.
Try your own numbers in the wind at altitude calculator.
What it can't see
A model grid cell is a few kilometres wide. A ridge, a tree line or tall buildings next to you can change the wind in ways no model resolves. Treat the figures as the forecast for open ground nearby, and check the verified badge to see how the forecast has done at the nearest airport.
What you get
Wind at your chosen altitude for today and the next 24 hours, with estimated gusts and the go/no-go score.
FAQ
Why does Altiwind show more wind than my weather app?
Your weather app shows the wind at 10 m. Altiwind shows it at the height you fly, which is usually stronger. In the example above, 18 km/h at 10 m becomes about 25.5 km/h at 120 m.
How accurate is the power law?
It is a standard approximation that works best over flat, open ground and less well near hills, coasts and towns. That's why Altiwind uses the model's own height levels first.
Does wind always increase with height?
In the lowest 120 m it usually does, but not always. Sea breezes, valley winds and showers can change the pattern, so check the hour-by-hour figures rather than assuming.