Winds aloft between levels
The wind and temperature at your cruising altitude from the forecast levels above and below it, interpolated as a vector so a turning wind turns smoothly.
Planning and education aid. Not for primary navigation. Full disclaimer
Experimental: not yet fully verified. How results are checked
At 7,500 ft expect wind from 288° at 24.2 kt.
- Wind speed
- Temperature
- u (toward east)
- v (toward north)
- Level below
- Level above
Provenance
- Computed by
- aviation.wind.aloft-interpolate 1.0.0, core 0.1.0
- Model
- Between the two forecast levels that bracket the altitude, u, v, and temperature vary linearly with altitude; the wind is read back from u and v. No extrapolation above the highest or below the lowest level. Forecast winds are true (Aviation Weather Handbook §27.2)
- Accuracy
- Exact for the linear model; the forecast's own error is larger
- Notes
- 1 shown with the answer
- Cites
- Federal Aviation Administration, Aviation Weather Handbook, FAA-H-8083-28B
Something look off?
How we got thisFormula, worked example, sources, and proof
Model: Between the two forecast levels that bracket the altitude, u, v, and temperature vary linearly with altitude; the wind is read back from u and v. No extrapolation above the highest or below the lowest level. Forecast winds are true (Aviation Weather Handbook §27.2)
Accuracy: Exact for the linear model; the forecast's own error is larger
Worked example: 7,500 ft between the 6,000 and 9,000 ft winds. Source: Hand check: u = (20 + 25.98)/2 = 22.99 kt, v = (0 - 15)/2 = -7.5 kt, so 288° at 24.2 kt; temperature 0 °C. It is golden test vector v001, and every build checks the tool still gives its answer within its tolerance.
You enter
- Your altitude
- 7500 ft
- Forecast levels
- 6000 ft, 270 deg, 20 kt, 3 °C 9000 ft, 300 deg, 30 kt, -3 °C
You get
- Wind direction
- 288°
- Wind speed
- 24.2 kt
- Temperature
- 0 °C
- u (toward east)
- 22.99 kt
- v (toward north)
- -7.5 kt
- Level below
- 6,000 ft
- Level above
- 9,000 ft
Review: Not yet independently reviewed by a flight instructor (CFI).
Last verified: 2026-09-23, when a maintainer last confirmed this tool's sources at the issuer. See the sources ledger.
Status: version 1.0.0, core 0.1.0. See this tool in the verification report.
Checked against: 7 golden test vectors (download the test vectors, each with its source and tolerance). See how results are checked and every source.
Sources
- Aviation Weather Handbook, FAA-H-8083-28B, Federal Aviation Administration, FAA-H-8083-28B. Section 8.4 (altimetry), section 3.4.2.14 and tables 3-17 and 3-18 (flight categories), section 24.4 (METAR and SPECI), section 27.2 (FB winds and temperatures aloft), and section 27.4 (TAF). Read free.
Experimental means this tool has not yet met the stable bar: at least 20 golden vectors, differential tests, and an independent worked example.
Learn the concept: How to read a winds aloft forecast