The zones and areas in this Annex are, in general, based
on the following criteria:
Summer - not more than 10 per cent winds of force
8 Beaufort (34 knots) or more.
Tropical - not more than 1 per cent winds of force
8 Beaufort (34 knots) or more. Not more than one tropical storm in
10 years in an area of 5° square in any one separate calendar
In certain special areas, for practical reasons, some degree
of relaxation has been found acceptable.
A chart is attached to this Annex to illustrate the zones and
areas defined below.
pMap Chart of zones and seasonal areas