Which of the following climatic belts has the highest durnal temperature range?

Analyze the question Diurnal temperature range is the difference between the highest (daytime) and lowest (night-time) temperature in a 24-hour period. The question asks which climatic belt has the largest range.

Explain the concept Diurnal range depends on how quickly the land heats and cools. It is large where:

• The sky is clear, with little cloud or humidity. Strong insolation heats the surface by day, and heat escapes rapidly by terrestrial radiation at night.
• The area is far from the sea, so there is no moderating maritime influence.
• There is little vegetation or moisture to store heat.

Go through the options

• A. Desert: The air is very dry, with almost no clouds or vegetation. Daytime temperatures can exceed 40°C, and night temperatures can drop to near 0°C or lower. The range is often 20-30°C or more. This is the largest of the four.
• B. Mediterranean: It is coastal and has a moderating maritime influence, so the range is moderate.
• C. Tropical Continental: The range is fairly large, especially in the dry season (Harmattan in Northern Nigeria), but it is generally smaller than in true deserts because there is more moisture and vegetation.
• D. Tropical Hinterland: This is a similar interior type, with a moderately high range, but it is less extreme than the desert.

Answer The desert has the highest diurnal temperature range because of its clear skies, dry air, and lack of moisture or vegetation to hold heat.

Exam tip Link "diurnal range" with dryness + clear skies + distance from the sea. When you see "highest diurnal range", think Desert (for example the Sahara). When you see "lowest", think equatorial or coastal areas.