World Climates
Chapter 21, Section 2
The Köppen Climate Classification
System
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The Köppen climate classification system uses
mean monthly and annual values of temperature
and precipitation to classify climates
The Köppen system has five principle groups:
humid tropical climates, dry climates, humid midlatitude climates, polar climates, and highland
climates
All of these, except dry climates, are defined by
temperature
Dry climates are classified according to the
amount of precipitation
Climates of the World
Concept Check
What is the Köppen climate classification
system?
 The Köppen system uses mean monthly
and annual values of temperature and
precipitation to classify climates.
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Humid Tropical Climates
Humid tropical climates are climates without
winters
 Every month in such a climate has a mean
temperature above 18ºC
 The amount of precipitation can exceed 200
cm per year
 Wet Tropical Climate – high temperatures
and much annual precipitation (Rainforests)
 Tropical Wet and Dry Climate – temperatures
and precipitation similar to the wet tropics, but
experience distinct periods of low precipitation
(Savannas)
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Rainforests vs. Savannas
Concept Check
Describe the characteristics of humid
tropical climates.
 Humid tropical climates have no winters.
Every month has a mean temperature
above 18ºC and has a lot of precipitation.
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Humid Mid-Latitude Climates
Climates with mild winters have an average
temperature in the coldest month that is below
18ºC but above -3ºC
 Climates with severe winters have an average
temperature in the coldest month that is below
-3ºC
 Humid mid-latitude climates include: humid
subtropical, marine west coast, dry-summer
subtropical, humid continental, and subarctic
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Humid Subtropical Climate – generally located
on the eastern side of a continent and
characterized by hot, sultry summers and cool
winters
Marine West Coast Climate – found on the
windward coasts from 40º and 65º latitude and
dominated by maritime air masses; winters are
mild, and summers are cool
Dry-Summer Subtropical Climate – located on
the west sides of continents between 30º and
45º latitude; the only humid climate with a strong
winter precipitation max
Subarctic Climate – found north of the humid
continental climate and south of the polar
climate; bitterly cold winters and short cool
summers; highest annual temperature range
Humid Mid-Latitude with Mild
Winters
Humid Mid-Latitude with Severe Winters
Concept Check
What type of climate does LA have?
Explain.
 LA has a dry-summer subtropical climate.
It is on the west-side of the continent,
located between 30º and 45º latitude, and
experiences all of its precipitation in the
winter.
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Dry Climates
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A dry climate is one in which the yearly precipitation is not as
great as the potential loss of water by evaporation
Dryness is not only related to annual rainfall, but is also a
function of evaporation
Evaporation is closely dependent upon temperature
There are two types of dry climates: arid (desert) and semi-arid
(steppe)
The steppe is a marginal more humid variant of the desert,
separating the desert from the humid climates
Dry climates exist as the result of the global distribution of air
pressure and winds
Other dry climates are a result of rain shadows off of large
mountain chains
Some of Earth’s driest climates occur where a cold ocean
current affects the west coast of a continent
Extent of Dry Climate Zones
Concept Check
What defines a dry climate?
 Both the amount of precipitation that falls
and the amount that can be lost as the
result of evaporation.
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Polar Climates
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Polar climates are those in which the mean
temperature of the warmest month is below 10ºC
Polar winters are periods of perpetual night,
making temperatures extremely cold
In the summer, temperatures remain cool despite
the long days
Very little precipitation falls in polar regions
There are two types of polar climates: the tundra
climate (treeless region) and the ice cap climate
(permanent ice and snow)
Two Types of Polar Climates
Concept Check
What are the characteristics of polar
climates?
 Polar climates are extremely cold, even in
the summer months. Very little
precipitation falls in polar regions, and
evaporation is limited.
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Highland Climates
Highland climates are localized
 They are much different than their
surrounding climates
 The conditions vary abruptly from one
place to another
 South-facing slopes are warmer than
north-facing slopes
 In general, highland climates are cooler
and wetter than nearby areas at lower
elevations
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Concept Check
How do highland climates compare with
nearby lowland climates?
 Highland climates are usually cooler and
wetter than nearby places at lower
elevations.
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Assignment
Read Chapter 21, Section 2 (pg. 592-599)
 Do Chapter 21 Assessment #1-32 (pg. 609610)
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