Wind at Altitude

How to read the table

Each row is one height above the ground: 10 m, 80 m, 120 m and 180 m. For each height you get:

• Direction, as a compass point, is where the wind is coming from, the usual weather convention. "SW" means a south-westerly wind.
• The arrow points where the wind is blowing to, which is the way your drone will drift if it stops holding position.
• Speed, in the unit you have selected, is the average wind for the current forecast hour, not a gust.

Gusts are only published at 10 m, so they appear as a note under the table. The higher rows show average wind only; don't read the lack of a gust figure as smoother air.

Four patterns to recognise

Steady increase with height. For example, 12 km/h at 10 m, 20 at 80 m, 23 at 120 m and 26 at 180 m, all from the same direction. This is the normal daytime pattern. Judge the flight by the 120 m figure, not the 10 m one.

Calm below, fast above. For example, 4 km/h at 10 m and 25 km/h at 80 m. The layers are not mixing, which is typical of clear nights, early mornings and late evenings. The change can be abrupt, so climb in steps and watch how the drone behaves. Our guide to wind shear covers this situation in detail.

Direction turning with height. For example, W at 10 m and NW at 120 m. Your drone will drift a different way once it climbs, and the headwind leg of your return may not be the one you expected from the ground.

Almost the same at every height. On windy, well-mixed days the wind can be nearly uniform from 10 m upwards. It is not calmer at height, and it is usually gusty.

Which row to use

• For your flight limits, use the row nearest the highest point of your flight. Most open-category and recreational flights top out at 120 m in Europe and the UK, or 400 ft (122 m) in the US, so the 120 m row is the one that matters most.
• The 180 m row is there for context. It shows whether the wind keeps increasing above your ceiling. In the US it is also relevant when flying above a tall structure, where Part 107 allows flight up to 400 ft above the structure within 400 ft of it.
• For the return leg, check the direction at your cruise height. If you will fly home into that wind, estimate the extra time and battery with the Return-to-Home calculator.

To see whether the wind at height is within your drone's limits, compare it with your drone profile in the Drone Wind Calculator. The Flight Condition Checker also rates the 120 m wind against the same limits as the surface wind.

"Above ground" means the model's ground

The heights are measured from the ground as the forecast model sees it. Models smooth the terrain over a grid several kilometres wide, so on a hilltop, a cliff edge or in a narrow valley, the model's "ground" may be tens of metres above or below where you actually stand.

In practice:

• On a hill or ridge, you are already partly exposed to the faster air the model puts higher up. Expect wind closer to the 80 m value even at low heights.
• In a sheltered valley, the surface may be calmer than the 10 m figure, but the wind above the valley rim can be close to the higher rows.
• Near buildings and trees, local turbulence isn't in the forecast at all.

This is a snapshot of the current hour

The table shows the current forecast hour only. The profile changes through the day: in the afternoon the air mixes and the rows tend to be closer together, while after sunset the lowest layer often calms down and the air above keeps moving. To see how it develops over the next days, open the Weather diagrams. To rate a specific future time, use Flight Window.