Climagraph
A special graph
to show both
temperature
and monthly
precipitation
at a place
Temperature
1
Philadelphia
Precipitation
cm(in)
°C(°F)
20(68)
10 (4)
(Room temp)
The number of months
with temperatures
above 50 degrees F
is a rough measure
of the growing season.
10(50)
0(32)
(Freezing)
4 (1.6)
0
J FMAMJ J ASOND
Month
Three simple rules
about climate
Winter temperatures get a lot colder
when you go farther from the Equator
a nd summers get cooler and shorter.
2
Both summer and winter get cooler
when you go up high mountains.
Precipitation decreases when you go inland,
away from the ocean (or large lakes).
OK, four: ocean currents complicate things.
©2011 P Gersmehl Teachers may copy for use in their classrooms. Contact [email protected] regarding permission for any other use.
Comparing environments in China and the United States
To help us compare China and the United States, we will use a special kind of graph
that shows average temperature and total precipitation for each month of the year.
The curving line shows the temperature
through the year from January to December.
The three horizontal lines help put the
temperature curve into perspective.
The bottom line shows 0 degrees Celsius
(32 degrees Fahrenheit), the temperature
at which water freezes. The top line shows
20 degrees Celsius (68 degrees Fahrenheit),
which is close to "ideal room temperature."
Those lines make it very easy to count
how many months are below freezing,
and how many months are hot enough
that people might want airconditioning.
Temperature
Philadelphia
Precipitation
cm(in)
°C(°F)
20(68)
10 (4)
(Room temp)
10(50)
0(32)
(Freezing)
4 (1.6)
0
J F M A M J J A S ON D
Month
The vertical bars show the total precipitation (rain and/or snow) in each month of the year.
The precipitation scale is adjusted to fit the temperature scale. The top horizontal line
indicates 10 centimeters of rain (about 4 inches). This is the amount of water trees need
in a month when the average temperature is about 20 degrees Celsius.
The bottom of the precipitation bars is a little bit higher than freezing temperature,
because plants usually don't grow until the temperature is a little above freezing,
and therefore they don't need any water.
If the precipitation bar for a month extends higher
than the temperature line, rain and snow provide
more water than plants are able to use in that month.
Some of that excess water can sink into the ground.
The rest will run off to form rivers (or even floods).
On the other hand, if the precipitation bar for a month
is lower than the temperature line, plants may not have
enough water to grow, unless there is some water
stored in the soil from previous months. In fact,
there may even be a fire hazard in that month.
Beijing
R
F
One last bit of background. China and the United States are about the same size
and are located about the same distance from the Equator (see p. 124 in your atlas).
We should therefore not be surprised to see that many parts of China are "climatic analogs"
for places in the United States. That means they are located in similar positions and therefore
have similar climates. For example, Beijing (the capital of China) has a location similar to
Philadelphia (the first capital of the United States). They both are located about 40 degrees
of latitude away from the Equator. They both are close to the east coast of their country.
They both have average winter temperatures close to freezing and about three months
when airconditioners would be useful to cool buildings to a pleasant room temperature.
The United States, however, has the Great Lakes. These large inland bodies of water
help give the eastern United States a little warmer winter with a little more rain and snow.
At the same time, they help keep things a little cooler in summer, which weakens the wind
and reduces the amount of excess rain in summer.