Humid Subtropical (Cfa)
The Humid Subtropical climate zone is found mostly on the eastern sides of continents
(Figure17.16). Rain falls throughout the year with annual averages between 80 and 165
cm (31 and 65 inches). Summer days are humid and hot, from the lower 30’s up to 40°C
(mid-80’supto104°F).Afternoonandeveningthunderstormsarecommon. Theseconditions
are due to warm tropical air passing over the hot continent. Winters are mild, but middle-
latitude storms called cyclones may bring snow and rain. The southeastern United States,
with its hot humid summers and mild, but frosty winters, is typical of this climate zone.
Figure 17.16: The humid subtropical climate zone is shown in green. ( 36 )Forests grow thickly in much of this region, due to the mild temperatures and high humid-
ity. Pine forests are common in the lower latitudes, while oak are more common at higher
latitudes (Figure17.17).
Marine West Coast Climate (Cfb)
This climate lines western North America between 40° and 65° latitude, an area known as
the Pacific Northwest (Figure17.18). Ocean winds bring mild winters and cool summers.
The temperature range between seasons and between day and night is fairly small. Rain falls
year-round, although summers are drier as the jet stream moves northward. Low clouds,
fog, and drizzle are typical. Snowfall is infrequent and short-lived. The mountain ranges
that line the western U.S. keep this climate from extending far inland.
Dense forests ofDouglas firthrive in the heavy rain and mild temperatures (Figure17.19).
In Western Europe the climate covers a larger region since no high mountains are near the
coast to block wind blowing off the Atlantic.
Continental Climates (Group D)
Continental (Group D) climates are found in most of the North American interior from
about 40°N to 70°N. In this climate, summers are cool-to-warm and winters are very cold