YY (Day of the month) (UTC)
01 First day of the month.
02 Second day of the month …etc.
DD (Time of observation)
To nearest hour (UTC).
iw (Wind speed indicator)
Code Description
0 Wind speed estimated [m/sec]
1 Wind speed from anemometer [m/sec]
3 Wind speed estimated [knots]
4 Wind speed from anemometer [knots]