Winds and temperatures aloft forecasts
How to read the FB winds-aloft forecast and use it for cruise altitude, ground speed and fuel planning.
The winds and temperatures aloft forecast (FB) predicts wind direction, speed and temperature at standard altitudes (3,000, 6,000, 9,000, 12,000, 18,000 ft and up) for forecast points across the country. It's the tool for picking a cruise altitude, estimating ground speed, and planning fuel.
A coded entry looks like `2429+04` at 9,000 ft:
- 24 — wind from 240° (true).
- 29 — 29 knots.
- +04 — temperature +4°C.
Decoding rules to remember:
- Winds are referenced to true north (charts and headings you fly are magnetic — apply variation).
- Speeds 51–86 encode winds of 100–199 knots by adding 50 to the direction and 100 to the speed (e.g. `7335` = 230° at 135 kt). A speed code of 99 means 199 kt.
- Light and variable winds appear as `9900`.
- The 3,000 ft level has no temperature, and levels within ~1,500 ft of the station are omitted.
Use it tactically: a strong tailwind a few thousand feet higher can cut your time and fuel burn; a headwind that strengthens with altitude argues for staying low. The temperature helps you anticipate the freezing level for icing and compute density altitude and true airspeed. Pair the FB with the winds your flight-planning app interpolates for your exact route and altitude.
*Reference and training only. Use official briefings for flight planning.*