To read a climate graph, find the two axes first, then read values month by month. Temperature is usually drawn as a line and rainfall as bars, each with its own scale and unit.
This skill opens the weather and climate module, and it supports every later lesson that uses monthly data.
What is on a climate graph?
The horizontal axis shows the twelve months. One vertical axis shows mean monthly temperature in °C. The other shows total monthly rainfall in mm.
Before you read anything, put a finger on each axis and say the unit aloud. That ten-second habit prevents the most common error in this topic.
How do you describe it, step by step?
- Name the axes and units.
- Temperature: state the highest and lowest monthly values with their months.
- Calculate the range by subtracting lowest from highest.
- Rainfall: state the wettest and driest months with values, and the annual total if asked.
- Pattern: say whether rain is spread evenly or concentrated in some months.
Worked example
The data below is invented for teaching, for a place called Town A.
| Month | J | F | M | A | M | J | J | A | S | O | N | D |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Temperature (°C) | 4 | 5 | 8 | 11 | 15 | 18 | 20 | 19 | 16 | 12 | 7 | 5 |
| Rainfall (mm) | 60 | 50 | 45 | 50 | 55 | 60 | 70 | 75 | 65 | 80 | 75 | 65 |
Temperature: the highest is 20 °C in July and the lowest is 4 °C in January. The range is 20 − 4 = 16 °C.
Rainfall: the wettest month is October with 80 mm and the driest is March with 45 mm. The annual total is 60 + 50 + 45 + 50 + 55 + 60 + 70 + 75 + 65 + 80 + 75 + 65 = 750 mm.
Pattern: rain falls in every month, with slightly more from July to December. The warmest months are June to August.
Written answer: “Temperature peaks at 20 °C in July and falls to 4 °C in January, a range of 16 °C. Rainfall occurs all year, from 45 mm in March to 80 mm in October, with an annual total of 750 mm.”
The mistake to watch for
A student reads a rainfall bar against the temperature scale.
Mistaken answer: “The highest temperature is 75 °C in August.”
The student read the height of the rainfall bar against the temperature numbers.
The correction is to ask which symbol you are reading: a bar means rainfall and mm, a line means temperature and °C. A temperature of 75 °C should also trigger a sense check, since no mean monthly temperature on Earth is that high.
Check yourself
Use the Town A table above.
1. In which month is the temperature 15 °C, and what is the rainfall that month?
Show answer
The temperature is 15 °C in May, and the rainfall is 55 mm.
2. What is the mean monthly rainfall for Town A?
Show answer
750 ÷ 12 = 62.5 mm.
3. Is the statement “the wettest month is also the warmest” true for Town A?
Show answer
No. The warmest month is July (20 °C, 70 mm), but the wettest is October (80 mm, 12 °C). So the statement is false.
Where this leads next
Next, turn the extremes you just read into a single number in calculate a temperature range. The statistics and distribution explorer lets you test means and ranges on your own figures. If graph descriptions are still where marks slip away, our teachers work on this in online one-to-one Geography tuition.