The difference between the hottest and coldest months of a place is the

Analyze the question: It asks for the term describing the difference between the temperature of the hottest month and the temperature of the coldest month at a place.

Concept: In climatology, temperature is described using several measures:

• Mean annual temperature: the average of all the monthly mean temperatures in a year (add up the 12 monthly means, then divide by 12).
• Annual range of temperature: the difference between the mean temperature of the hottest month and that of the coldest month.
• Diurnal range: the difference between the highest and lowest temperatures in a single day.
• Total monthly temperature: not a standard climatic measure.

Step-by-step solution:

1. The question mentions the hottest month and the coldest month, so it is about the whole year.
2. The difference between two extremes is a range.
3. Over a year, this is the annual range of temperature.

Annual range = Mean temperature of hottest month − Mean temperature of coldest month

Example: If Kano's hottest month is 32°C and its coldest is 22°C, the annual range = 32 − 22 = 10°C.

Checking the options:

• A. Length of the hot season: this is about duration, not a temperature difference. ❌
• B. Mean annual temperature: this is an average, not a difference. ❌
• C. Annual range of temperature: correct. ✅
• D. Total monthly temperature: not a recognised climatic term. ❌

Answer: C. Annual range temperature

Exam tip: Remember that range = highest − lowest. If the question says "hottest and coldest months," think annual range. If it says "highest and lowest in a day," think diurnal range. Also, places near the equator, like Port Harcourt, have a small annual range, while places in the interior, like Sokoto, have a larger one.