What is Climate?
17-1 pgs. 452-457
April 6, 2015
IN: What is the difference
between weather and
climate? Describe our
Terms and Objectives:
 Terms:
Weather Latitude
Prevailing winds
Surface Currents
 Objectives:
• Explain the difference between weather
and climate.
• Identify the factors that determine
Climate – the average
weather conditions in an area
over a long period of time.
What determines climate?
our average temp is 80 and
average precipitation is 4”.
What is the difference between
climate and weather?
 Weather
is the condition at a
particular time and place.
 Weather conditions vary from
day to day.
Different parts of the world
experience different climates.
Different parts of North America
experience different climates.
What are climates so
Wind patterns
Ocean currents
Latitude – the distance north
or south from the equator.
Latitude determines the
amount of solar energy a
particular area receives.
The sun’s rays
strike the Earth’s
surface at
different angles
because the
surface is
Prevailing Winds – winds that
blow mainly from one
How do prevailing winds affect
our climate?
In North
America winds
tend to blow
from the west to
the east.
The prevailing
winds move air
 The
Rain Shadow Effect
DIAGRAM in your journals.
 The maritime air mass over the ocean is
humid. Prevailing winds blow the air
toward the mountains in the east.
 The air cools, becoming saturated as it is
forced into higher altitudes. The water
vapor condenses, precipitating on the
“windward” side of the mountain.
 As the air crosses the “leeward” side of
the mountains, and falls to lower
elevations, it warms and any remaining
water returns to being vapor creating a
dry climate.
Surface Currents – a
streamlike movement of water
that occurs at or near the
surface of the ocean.
Ocean Currents flow in curved
patterns because of the
Coriolis Effect, just like air.
How do ocean currents affect
 Maritime air masses that form over cooler
surface currents will hold less water vapor than
maritime air masses that form over warm
surface currents.
 Regions that are near warm surface currents
will have a more humid climate than those near
a colder surface current.
 The surface current on the West Coast of the
US flows from Alaska and is cold, while the
East Coast is more humid from a tropical
current called the Gulf Stream.