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5 Factors That Affect Climate
What is the weather like outside today? What will the weather be like this whole season?
What type of weather are you expecting for the summer? If it is winter and you live in
Michigan, you might expect the weather to be a cold day around 30 o with possible snow.
Weather is the day to day changes in the air. You know that there are surprise days in
February that the weather is 55o. Climate is the average weather in an area. The average
is calculated from the weather that had occurred over a long period of time. The climate
includes the temperature and precipitation that an area receives. As geographers, we will
discuss the climate rather than the weather. Remember, climate is what you expect and
weather is what you get!
There are five factors that play a role in an area’s climate. The five factors
are: the
latitude zone, the elevation of the land, topography (landforms),
ocean currents
and winds.
1. Climate Zones and Climate Regions
The first factor that affects climate is where a place is located on earth. The
Earth is round and tilted on its axis, so the sun’s rays reach the Earth in different
ways. The rays are strongest and more direct at the Equator. However, the rays
are not as strong and are less direct at the poles. According to where the sun’s
rays differ, we divide the Earth into three climate zones. There are special lines of
latitude that divide each climate zone. Each zone has particular climate regions.
The special lines of latitude are dotted lines are used because they are half numbers.
The lines are named because they separate the main climate zones.
North Pole 90oN
Arctic Circle 66 ½oN
Tropic of Cancer 23 ½oN
Equator 0o
Tropic of Capricorn 23 ½oS
Antarctic Circle 66 ½oS
South Pole 90oS
LOW ZONE: The lowest latitude lines are between 0o to 23½o. This climate zone is called the low latitude
zone. The climate here is tropical, which is generally warm and rainy all year. The Tropical Region is
between the Tropic of Cancer (23½oN) and the Tropic of Capricorn (23½oS). This area receives the most
direct heat from the sun all year.
HIGH ZONE: The highest latitude numbers are between 66½o to 90o. This climate zone is called the high
latitude zone. The climate here is polar; generally it’s cold and snowy all year. Polar Regions are between
the Arctic Circle to the North Pole and between the Antarctic Circle to the South Pole. They receive the
least direct heat of the sun.
MIDDLE ZONE: The latitude lines between 23½o to 66½o are the middle latitude zones. The middle
latitudes fall between the Tropic of Cancer and the Arctic Circle, and between the Tropic of Capricorn and
the Antarctic Circle. The areas closer to the low latitudes/tropics have moderate climate. The summers
are warm, and the winters are mild and rainy. The areas closer to the high latitudes/polar have a
continental climate. The summers are warm, and the winters are cold and snowy.
MORE CLIMATE REGIONS:
Throughout the different climate zones there are areas that have dry climates. These places receive very
little precipitation throughout the year. Dry or arid areas receive less than 10 inches of annual
precipitation. Other dry areas are semi-arid areas receive 10-20 inches of annual precipitation. There are
reasons why these areas lack precipitation that will be discussed later.
2. Elevation
The second factor that can affect the climate is the elevation of a place. The
temperature drops at higher elevations. The air becomes thinner as you move up in
elevation. Thin air cannot hold on to heat so the air feels colder. If you were in a
city that had a mountain, you would experience different climate even though you
are in the same latitude zone. The ground below can have grass and flowers and all
you need is a jacket. At the same time, the mountain can have snow on top and you
would need warmer clothes.
3. Topography (landforms)
The third factor that can affect climate are landforms. Mountains can create a rain
shadow effect which causes cities in the same latitude zones to have different climates.
Rain clouds form above the ocean and bring precipitation to coastal lands. A mountain can
prevent the rainfall from reaching the other side. The climate for the land on the other
side of the mountain will become dry or arid due to the lack of precipitation. The states
of California and Nevada are great examples of where rain shadows have affected the
climate. The appropriately named Death Valley in the United States is the driest place in
North America and one of the driest places on the planet. Death Valley was formed in
part of the rain shadow affect by the Pacific Coast Ranges of California and the Sierra
Nevada Range.
4. Ocean Currents
The fourth factor that affects the climate is the ocean currents. An ocean current is
like a river moving in the ocean. We will watch a video clip from “Finding Nemo” that will
best display how an ocean current looks and acts in the ocean. The ocean currents affect
the temperature of landmasses they pass bringing either warm or cool winds. Warm ocean
currents originate from the waters in the tropics and travel to places further away,
bringing warm winds to lands that would normally have colder climates. Then, there are
cool ocean currents that originate near the poles that bring cool winds to lands further
away from the poles.
5. Winds
The final factor that affects the climate is the winds. The Earth rotates and that is a
simple explanation for the cause of wind. The winds assist the earth not to overheat from
the sun’s rays. Warm winds from the tropics spread warm air around the world. Cool air
from the poles spread cool air around the world. Let’s look at two cities that are on the
same line of latitude but have varying climates.
Let’s compare San Francisco, California and St. Louis, Missouri that are both on the 40oN.
San Francisco California is a coastal city. The sun warms up the land faster than it warms
the ocean. So the ocean winds can cool the land, so the summers are cool and the winters
are mild. St. Louis is an inland city and cities away from the ocean have extreme
differences. The summers are hot and the winters are very cold.
40o N