h tropical
conditions. Cyclonic and anticyclonic spells of hotter or cooler, rainy
or dry, weather, with varying winds differing in the temperatures and
the moisture which they bring, serve to break the regularity of the
diurnal types. In winter the non-periodic, cyclonic control is
strongest. The irregular changes from clear to cloudy, from warmer to
colder, from dry air to snow or rain, extend over large areas, and show
little diurnal control. Spring and fall are transition seasons, and have
transition weather types. The south temperate zone oceans have a
constancy of non-periodic cyclonic weather changes through the year
which is only faintly imitated over the oceans of the northern
hemisphere. Winter types differ little from summer. The diurnal control
is never very strong. Stormy weather prevails throughout the year
although the weather changes are more frequent and stronger in the
colder months.

_Climatic Subdivisions._--There are fundamental differences between the
north and south temperate zones. The latter zone is sufficiently
individual to be given a place by itself. The marginal sub-tropical
belts must also be considered as a separate group by themselves. The
north temperate zone as a whole includes large areas of land, stretching
over many degrees of latitude, as well as of water. Hence it embraces so
remarkable a diversity of climates that no single district can be taken
as typical of the whole. The simplest and most rational scheme for a
classification of these climates is based on the fundamental differences
which depend upon land and water, upon the prevailing winds, and upon
altitude. Thus there are the ocean areas and the land areas. The latter
are then subdivided into western (windward) and eastern (leeward)
coasts, and interiors. Mountain climates remain as a separate group.

_South Temperate Zone._--Because of the large ocean surface, the whole
meteorological regime in the south temperate zone is more uniform than
in the northern. The south temperate zone may properly be called
"temperate." Its temperature changes are small; its prevailing winds are
stronger and steadier than in the northern hemisphere; its seasons are
more uniform; its weather is prevailingly stormier, more changeable, and
more under cyclonic control. The uniformity of the climatic conditions
over the far southern oceans is monotonously unattractive. The
continental areas are small, and develop to a limited degree only the
more