Code Figure Descriptive terms Height* (in meters)
0 Calm (glassy) 0
1 Calm (rippled) 0 - 0.1
2 Smooth (wavelets) 0.1 - 0.5
3 Slight 0.5 - 1.25
4 Moderate 1.25 - 2.5
5 Rough 2.5 - 4
6 Very rough 4 - 6
7 High 6 - 9
8 Very high 9 - 14
9 Phenomenal Over 14
Notes:
(1) * These values refer to well-developed wind waves of the open sea. While priority shall be given to the descriptive terms, these height values may be used for guidance by the observer when reporting the total state of agitation of the sea resulting from various factors such as wind, swell, currents, angle between swell and wind, etc.
(2) The exact bounding height shall be assigned for the lower code figure;
e.g. a height of 4 m is coded as 5.
Table 3155: Period of waves
Code Meaning
0 10 seconds
1 11 seconds
2 12 seconds
3 13 seconds
4 14 seconds or more
5 5 seconds or less
6 6 seconds
7 7 seconds
8 8 seconds
9 9 seconds
/ Calm or period not determined
NODC Code Table 1555: Wave height (modified from WMO code table 1555)
Code Meaning
0 calm
1 0.5 meter
2 1 meter
3 1.5 meter
4 2 meter
5 2.5 meter
6 3 meter
7 3.5 meter
8 4 meter
9 4.5 meter
10 5 meter
11 5.5 meter
12 6 meter
13 6.5 meter
14 7 meter
15 7.5 meter
16 8 meter
17 8.5 meter
18 9 meter
19 9.5 meter
20 10 meter
21 10.5 meter
22 11 meter
23 11.5 meter
24 12 meter
25 12.5 meter
26 13 meter
27 greater than 13 meters
https://www.nodc.noaa.gov/woce/woce_v3/wocedata_1/woce-uot/document/wmocode.htm
