Geoscience Reference
In-Depth Information
Köppen Climate DesignationsT
T A B L E 9 . 1
First Letters
Derivation
Distinguishing Characteristic
A
Alphabetical
Mean temperature each month >18°C (64°F).
B
Alphabetical
Mean annual precipitation <76 cm (30 in.).
C
Alphabetical
Mean monthly warmest temperature >10°C (50°F) in warmest month; mean
monthly coldest temperature between 18°C and -3°C (64°F-27°F) in coldest month.
D
Alphabetical
Mean temperature >10°C (50°F) in 4-8 months.
E
Alphabetical
Mean temperature <10°C (50°F) in all months.
H
Alphabetical
Significant climate changes due to altitude variations.
Second Letters
F
German feucht, “moist”
6 cm (2.5 in.) of mean rainfall in each month.
M
Monsoon
Only 1-3 months with mean rainfall <6 cm (2.5 in.).
Summer dry season, with driest month having <
3
the mean precipitation of
wettest winter month.
S
Summer dry
S
Steppe (semi-arid)
Mean annual precipitation in low latitudes is 38 cm-76 cm (15 in.-30 in.), whereas
it is between 25 cm and 64 cm in midlatitudes. No distinct seasonal trend in either
latitude range.
T
Tundra
At least 1 month with mean temperature between 0°C and 10°C (32°F-50°F).
W
Winter dry
Winter dry season, with 3-6 months of <6 cm (2.5 in.) of mean rainfall in
A
climates. In
C
and
D
climates, the driest month has <
_
10
the mean precipitation of
the wettest summer month.
W
German wüste, “desert”
Mean annual precipitation <38 cm (15 in.) in low latitudes and <25 cm (10 in.) in
midlatitudes.
Third Letters
A
Alphabetical
Warmest month has mean temperature <22°C (71.6°F).
B
Alphabetical
Warmest month has mean temperature <22°C (71.6°F), but has 4 months with
mean temperature >10°C (50.0°F).
C
Alphabetical
Warmest month has mean temperature <22°C (71.6°F); fewer than 4 months with
mean temperature >10°C (50.0°F).
D
Alphabetical
Same as
C
, but coldest mean monthly temperature <-38°C (-36.4°F).
H
German heiss, “hot”
Mean annual temperature >18°C (64.4°F).
K
German kalt, “cold”
Mean annual temperature <18°C (64.4°F).
between major vegetation regions on Earth and regional climate
characteristics. The Köppen system describes world climates
based on average monthly temperature, average monthly pre-
cipitation, and total annual precipitation. It is such a widely
used system in part because these variables are measured more
frequently in many more places around Earth than any other
climate variables. Although the system is great for character-
izing regional climate conditions, it ignores more local factors
such as wind speed and cloud cover, which often influence
conditions dramatically in specific areas.
The best way to view the Köppen system is as a hierar-
chical classification scheme of categories and subcategories.
