Lesson 6 Climatographs

  Reading Climatographs

© By NASA, via Wikimedia Commons
DS2.4 Climatograph

A climatograph is a graph containing two sets of data: one for the average temperature and one for the average amount of precipitation each month. The months of the year are listed along the x-axis while the average precipitation and average temperature are listed along the y-axis. The average precipitation is generally found on the left side of the graph, while the average temperature is found on the right. Image DS2.4 is an example of a climatograph. The average temperature is represented by the line graph, and the average precipitation is represented by the bar graph. When reading the temperature, you would follow the point on the line graph to the right. When reading the precipitation, you would follow the point on the bar graph to the left.

Examples

Example 1

Image D6.1 shows the climatograph for Hinton, Alberta.

1. What is the average temperature in June?
   
   
   
   

   

   D6.1 Climatograph of Hinton AB

   
   
   
   

Check your work.

Use the temperature line graph to determine the temperature.

To answer this question, you need to find where June hits the line graph and follow it right.

D6.2 Average temperature in June

We will have to estimate based on where our dotted line falls, but the average temperature in June is approximately 12 ˚C.

2. What is the average precipitation in December?
   
   
   Check your work.
   

   
   Use the precipitation bar graph to determine the precipitation.
   
   To answer this question, you need to find the December bar and follow the top of it to the left.
   
   

   
   

   

   D6.3 Average precipitation in December

   
   

   
   We will again have to estimate based on where our dotted line falls, but the average precipitation in December is approximately 22 mm. It is important to note that when creating a climatograph, snowfall is converted into mm of rainfall. Generally, 10 mm of snow is equal to 1 mm of rain; so 22 mm of rainfall in December is equivalent to 220 mm of snow.
   
   

When comparing two climatographs, the same scale is used on both so they can be easily compared.

Example 2

Compare the climates of Hinton, Alberta, and Lethbridge, Alberta.

D6.1 Climatograph for Hinton, Alberta

D6.4 Climatograph for Lethbridge, Alberta

Check your work.

Notice how even though the climatograph for Lethbridge uses less space within the graph, it has the same scale as the climatograph for Hinton. This allows us to easily compare the two graphs. There are a few things you may notice:

• The pattern of both cities is very similar. It is much warmer in the summer months than in the winter months, with a drastic drop in temperature for January. Both cities see a spike in precipitation during the summer.
• The differences are also easily seen. Lethbridge does not get as cold as Hinton, and it is warmer in the summer. Hinton receives more precipitation throughout the year and has a more gradual increase and decrease in precipitation.

Using the knowledge you have gained in this unit, why do you think these cities differ in climate?

To answer this question, we need to think about all the causes of climate.

Check your work.

Let’s look at each factor in turn:

• Insolation: Hinton is slightly farther north than Lethbridge, so it will have slightly less insolation. This would cause the colder climate seen in Hinton. They are pretty close in latitude though, so we do see a similar pattern in seasons.
• Global winds: Both of these cities are within 30˚ N and 60˚ N, so the westerlies prevail in both cities. This causes some of the similarities seen.
• Large bodies of water: Neither city is near a large body of water.
• Mountains: This is the biggest reason for the difference in climate between these cities. Hinton is located right on the border of the Rocky Mountains and so gets some of the rain and snowfall that the mountains see. Lethbridge is in a rain shadow from the Rocky Mountains and so sees much less precipitation. It also sees chinooks that raise its average temperature in the winter.

What biome would each be located in?

Check your work.

To determine which biome each city is located in, we need to compare the climates with those of each biome.

Lethbridge has an annual temperature between –10 ˚C and 18 ˚C. It has an annual precipitation between 12.5 mm and 70 mm. When we compare this to the different biomes, Lethbridge best fits into the grassland biome, with its lower precipitation, hotter summers, and cold winters.

Hinton has an annual temperature between –12.5 ˚C and 15 ˚C. It has an annual precipitation between 20 mm and 85 mm. When we compare this to the different biomes, Hinton best fits into the taiga biome, with its cool summers, cold winters, and higher precipitation.

  Read This

  Practice Questions

1. Using the climatograph shown in image D6.5, what is the average temperature in December? What is the average amount of precipitation in August?
   
   
   
   

   

   D6.5 Climatograph for Medicine Hat
   
   
   Check your answer
   

   
   

   The average temperature in December is –8 ˚C, and the average precipitation in August is 37 mm. Both of these values are approximate based on estimating from the graph.
   

2. What are climatographs used for?
   
   
   Check your answer
   

   Climatographs are used to quickly see the climate of a location. They tell us lots of information about the average temperature, the average amount of precipitation, and how far north or south a place is located. From this, we can predict what biome that place is part of and compare climates between two locations.