Temperature range is the highest value minus the lowest value in whichever set of data you are given. It tells you how much the temperature varies, and questions ask for it with a unit.
It follows directly from reading values in read a climate graph correctly and is part of the weather and climate module.
Which range does the question want?
- Daily (diurnal) range: highest minus lowest temperature within one day.
- Annual range: warmest monthly mean minus coolest monthly mean.
The method is identical. Only the data changes, so check the labels first.
How do you calculate it, step by step?
- Underline the two numbers you need: the largest and the smallest.
- Write the subtraction as highest − lowest.
- If the lowest is negative, subtracting it means adding its size.
- Add the unit, °C.
- Sense check: the range cannot be negative.
Worked example
All data below is invented for teaching.
Part A, annual range. Town B has monthly mean temperatures of 26.7, 27.0, 27.4, 27.8, 28.4, 27.9, 27.5, 27.3, 27.2, 27.0, 26.9 and 26.8 °C. The warmest is 28.4 and the coolest is 26.7.
Range = 28.4 − 26.7 = 1.7 °C.
Part B, daily range with a negative. One winter day in Town C, the highest temperature is 6 °C and the lowest is −4 °C.
Range = 6 − (−4) = 6 + 4 = 10 °C.
Check by counting on a number line: from −4 up to 0 is 4 degrees, then from 0 up to 6 is 6 more. That is 10 in total, which matches.
The mistake to watch for
Mistaken answer: “6 − 4 = 2 °C.”
The student ignored the minus sign on −4 and treated it as 4.
The error makes the range look small when the day actually had a large spread. The correction is to write the brackets, 6 − (−4), and rewrite the subtraction as an addition. If you need practice with signs, revisit order signed numbers on a number line.
Check yourself
1. The highest temperature on a day is 12 °C and the lowest is −3 °C. Find the daily range.
Show answer
12 − (−3) = 12 + 3 = 15 °C.
2. A place has a warmest monthly mean of 24.8 °C and a coolest of 22.1 °C. Find the annual range.
Show answer
24.8 − 22.1 = 2.7 °C.
3. The highest temperatures on five days were 29, 31, 30, 32 and 28 °C. Find the mean of these five values, then the range.
Show answer
Sum = 29 + 31 + 30 + 32 + 28 = 150, and 150 ÷ 5 = 30 °C. The range is 32 − 28 = 4 °C.
Where this leads next
Continue with explain a rainfall mechanism with a diagram, then test the whole module in the practice set. The statistics and distribution explorer can check your means and ranges. If you understand this lesson but slip under timed conditions, online one-to-one Geography tuition can help you build a reliable routine.