3.3 Wind
The wind forecast group is the first entry for the initial valid period and any subsequent "From" (FM) groups. It will always be included, regardless of wind speed. [Note: "FM" groups are covered in more detail in Lesson 4:Forecast Change Groups].
Example of a wind group:
TAF
KABC 011136Z 0112/0212 22015KT...
| Description | Example |
| The first three digits are the mean wind direction rounded to the nearest 10 degrees. | 220 |
| The next two digits are the mean wind speed in knots followed by "KT" for knots. | 15 KT |
In the example above, 22015KT, means that the mean wind direction is forecast to be from 220 degrees with a wind speed of 15 knots.
Wind gusts (rapid fluctuations in speed expected to be 10 knots or more) if applicable, are added to the wind speed and direction coding.
| Description | Example |
| Wind gusts are indicated by using the letter "G" followed by the forecast gust value, followed by "KT" for knots. | 15020G35KT |
Variable (VRB) winds (variations in wind direction greater than or equal to 30 degrees) may be forecast when a mean direction is impossible to predict such as the case with light and variable winds or winds associated with a thunderstorm. The wind direction digits are replaced with the contraction "VRB" followed a wind speed and gusts if applicable.
| Description | Example |
| Wind speeds are 6 knots or less | VRB03KT |
| Strong gusty winds associated with a thunderstorm | VRB25G45KT |
Calm winds are forecast as 00000KT.
Wind direction forecasts even at low speeds can be extremely important in airport operations. Wind direction determines which runways are to be used for takeoffs and landings.
Forecasts of low wind speeds can be critical as well, especially if the runway(s) are impacted by ice, snow, or water, creating tighter tailwind and crosswind aircraft tolerances.