The ASOS wind sensor employs a "light chopper," electro-optical method to determine wind speed and convert it to appropriate electro-magnetic signals. Wind sensor measurements conform to the Range, Accuracy, Resolution specifications described in the table below. In addition, the sensor's starting threshold for response to wind direction and wind speed is 2 knots. Winds measured at 2-knots or less are reported as calm.

For wind direction, ASOS reports a 2-minute average of 5-second average wind directions once a minute (i.e., 24 samples each minute) for distribution through the One-Minute Observation (OMO) and computer-generated voice messages. The current 2-minute average wind direction is updated on selected Operator Interface Device (OID) screen displays once every minute and included in the transmitted METAR/SPECI messages. The direction from which the wind is blowing is reported to the nearest 10-degree increment (e.g., 274 degrees is reported as 270 degrees). Wind direction is reported relative to true north in the METAR/SPECI message, in the daily/monthly summaries, and on all video displays. Wind direction is reported relative to magnetic north in the computer-generated voice messages, and on the OID "AUX" data display screen.

A 2-minute average for wind speed is updated once every 5 seconds and is reported once every minute in the OMO and computer-generated voice messages, and included in the METAR/SPECI message and various OID screen displays.

Wind gust is a basic component of wind character and is updated every 5 seconds. It is appended to and reported with the basic wind observation only when appropriate conditions for reporting wind gusts exist. Wind gust information is included in the current OMO, computer-generated voice messages, the METAR/SPECI, and OID displays.

The wind shift remark is reported in the OMO and the METAR/SPECI when appropriate.

Variable wind direction is reported in the OMO and the METAR/SPECI when appropriate.