Free tool
Winds aloft decoder
The winds and temperatures aloft forecast, decoded. Direction, speed and temperature at every altitude level.
Region
Valid in
Levels
Fetching the bulletin.
Direction is degrees TRUE, not magnetic. A dash means the level is within 1,500 ft of the station and not forecast. Amber marks the over-100-knot encoding. The group as it arrived is under each cell.
How this works
- How the encoding works
- Each group has six digits: two for direction (tens of degrees), two for speed (knots), and two for temperature (Celsius). Above 100 knots the direction gets 50 added and the speed gets 100 subtracted, because the speed field is only two digits wide. 731960 means 230 degrees at 119 knots, not 730 at 19. Above 24,000 ft the temperature sign is dropped and the value is always negative. 9900 means light and variable.
- A blank is not a calm
- A missing group means the altitude is within 1,500 ft of the station. No forecast is issued that close to the ground. A station at high elevation will have blank rows at low altitudes.
- Direction and coverage
- Wind directions are in degrees true, the same reference as a METAR. Each bulletin covers one region and a set of reporting stations. The forecast is issued four times a day. The valid period is printed at the top.
Standard (below 100 kt)
231545
•23 × 10 = 230°
•15 kt
•−45°C
Above 100 kt
731960
•73 − 50 = 23 × 10 = 230°
•19 + 100 = 119 kt
•−60°C (above 24,000 ft, always negative)
Wind on the ground instead?
The crosswind calculator reads the current METAR at a field and gives the headwind and crosswind for every runway.
Open the crosswind calculatorAnd the forecast at the field
The TAF decoder reads a terminal forecast as a timeline, showing which periods replace the forecast and which overlay it temporarily.
Open the TAF decoderNot a substitute for an official pre-flight weather briefing.