The report modifier AUTO identifies the METAR/SPECI as a fully automated report with no human intervention or oversight. In the event of a corrected METAR or SPECI, the report modifier “COR” is substituted for “AUTO.”

Wind is the horizontal motion of air past a given point. It is measured in terms of velocity, which is a vector that includes direction and speed. It indicates the direction the wind is coming from.

In the wind group, the wind direction is coded as the first three digits (220) and is determined by averaging the recorded wind direction over a two-minute period. It is coded in tens of degrees relative to true north using three figures. Directions less than 100 degrees are preceded with a 0. For example, a wind direction of 90° is coded as 090. A wind from the north is coded as 360.

Immediately following the wind direction is the wind speed coded in two or three digits (15). Wind speed is determined by averaging the speed over a two-minute period and is coded in whole knots using the units, tens digits, and, when appropriate, the hundreds digit. When wind speeds are less than 10 kt, a leading 0 is used to maintain at least a two-digit wind code. For example, a wind speed of 8 kt will be coded 08KT. The wind group is always coded with a KT to indicate wind speeds are reported in knots. Other countries may use km/h or meters per second (m/s) instead of knots.

Examples:

05008KT Wind 50° at 8 kt

15014KT Wind 150° at 14 kt

340112KT Wind 340° at 112 kt

Wind speed data for the most recent 10 minutes is examined to evaluate the occurrence of gusts. Gusts are defined as rapid fluctuations in wind speed with a variation of 10 kt or more between peaks and lulls. The coded speed of the gust is the maximum instantaneous wind speed.

Wind gusts are coded in two or three digits immediately following the wind speed. Wind gusts are coded in whole knots using the units, tens, and, when appropriate, the hundreds digit. For example, a wind out of the west at 20 kt with gusts to 35 kt would be coded 27020G35KT.

Wind direction may be considered variable when, during the previous two-minute evaluation period, the wind speed was 6 kt or less. In this case, the wind may be coded as VRB in place of the three-digit wind direction. For example, if the wind speed was recorded as 3 kt, it would be coded VRB03KT.

Wind direction may also be considered variable when, during the two-minute evaluation period, it varies by 60° or more and the speed is greater than 6 kt. In this case, a variable wind direction group immediately follows the wind group. The directional variability is coded in a clockwise direction and consists of the extremes of the wind directions separated by a V. For example, if the wind is variable from 180 to 240° at 10 kt, it would be coded 21010KT 180V240.