Diurnal range of temperature is the

Diurnal range of temperature refers to the difference between the highest and the lowest temperature during a day. This means that the correct option is "difference between the highest and the lowest temperature for a day". For example, if the highest temperature in a day is 30°C and the lowest temperature is 20°C, the diurnal range of temperature for that day is 10°C. The other options listed are incorrect because: - The average of the highest and the lowest monthly temperature does not give information about the temperature range within a day. - The difference between the maximum and the minimum temperature for a year or a month does not necessarily give information about the daily temperature range. - The average of the minimum and the maximum daily temperature does not provide information about the daily temperature range as it only calculates an average value.