Below 40° south latitude, the climate is
progressively drier and cooler. However, the extreme
southern tip of South America is characterized by year
round cold and damp climate due to a strong maritime
West Coast Climate
The West Coast, from northern Peru to the middle
of Chile, is a desert. North and south of this desert
midsection, the climate is quite humid. The northwest
coast has a typical tropical climate with wet and dry
Below central Chile, the climate again shows a
typical Southern Hemisphere seasonal reversal of that
found in North America. The weather in this region is
similar to that found along the northwest coast of North
America. The climate is generally rainy and cool.
Summer does not seem to exist as we know it. Yet,
winter temperatures average above freezing.
Africas climate is unlike that of any other
continent for several reasons. The most important is the
fact that the entire continent is within the tropical zone.
The equator bisects the continent; therefore, in the area
north and south of the equator, the climates are similar,
yet they differ because the region north of the equator is
much larger than the southern region. Since the
northern area is so broad in the east-west direction,
maritime effects inland are minimal. Also, an extensive
low-pressure area develops inland due to extreme land
mass heating. A belt of high pressure, however, with its
maritime influences dominates the southern section,
during winter and by low pressure during summer.
Another factor is the cold currents, which exist
along its western shores. These currents allow an influx
of cool winds and associated weather to the West Coast.
The final factor involves the lack of high mountain
ranges common to other continents. Since there are no
prominent mountain ranges, the various climate types
in Africa blend together, showing no sharp distinctions.
The most important climatic element in Africa is
precipitation. Precipitation is greatest near the equator
(60 to 80 inches to over 120 inches in places). It
decreases sharply to the north (less than 10 inches), and
decreases gradually south of the equator (average of 20
to 40 inches). Because Africa is in the tropical zone, the
precipitation belt of the intertropical convergence zone
precipitation moves northward in the summer and
southward in the winter. Africa does have distinct
climatic regions. Air-mass movement and influences
allow for a division of eight climatic regions.
The northern region includes the great Sahara
desert. The desert is a source region for dry
continental-type air masses. While maritime air may
transit the area, the air masses are highly modified and
often exhibit continental properties after moving
inland. This desert region is extremely hot during the
day throughout the year but is very cool at night due to a
lack of moisture; hence, strong radiational cooling.
The southwest region is an arid to semiarid area,
temperatures are not as extreme as in the Sahara
because the land area involved is much smaller.
North Central Region
The north central region is a semiarid area located
along the edge of the Sahara. While the temperatures
are similar to those of the neighboring desert (50°F in
winter to well above 80°F in summer), this area
occasionally gets precipitation in the winter. The source
of this precipitation for the northern area is maritime air
from the Mediterranean; in the south, it is the spotty
rainfall provided by the meandering ITCZ.
The sub-equatorial region extends toward the
equator from the semiarid region in the north. The
region is marked by seasonal rainfall associated with
the position of the ITCZ. The region is wet for about 5
months (Nov-Mar), and dry during the rest of the year.
Temperatures show little seasonal variation (68°F to
86°F) because of the close proximity to the equator.
The only exception to this temperature stability occurs
in the western portion which, during the winter, is
occasionally influenced by cool weather from the
The equatorial region includes the southwest tip of
northern Africa and the region between 5° north and
south latitudes, extending from the western coast to
Lake Victoria. It is the wettest climate in all Africa.