N - Total amount of cloud
Code Amount of sky covered
0 None (cloudless).
1 One eighth of sky covered or less, but not zero.
2 Two eighths of sky covered.
3 Three eighths of sky covered.
4 Four eighths of sky covered.
5 Five eighths of sky covered.
6 Six eighths of sky covered.
7 Seven eighths of sky covered or more, but not eight eighths.
8 Eight eighths (sky completely covered).
9 Sky obscured by fog or other meteorological phenomena.
/ Cloud cover obscured for other reasons or not observed.
dd - Direction of surface wind
True direction from which the wind is blowing, to the nearest ten degrees, given in
the first two figures of the 360° notation, e.g.
Code Direction
00* calm
01 010°
02 020°
09 090°
18 180°
36 360°
99 variable
(*A northerly wind must always be coded as 36 and never 00)
Note
- For intermediate values
the higher value is coded, e.g. 125° is coded 13
ff - Speed of surface wind in knots or m/s
Wind speed in units indicated by iw, e.g.
Code* Beaufort scale
00 0
01-03 1
04-06 2
07-10 3
11-16 4
(*If iw indicates units in knots)
Note
- When the wind speed, in
units indicated by iw is 99 units or more, ff above is reported as
99 and the group 00fff is reported immediately after the group Nddff.