Diurnal range of temperature
Also called: Daily range of temperature, Daily and annual range of temperature, Diurnal range · Topic: Solar Radiation, Heat Balance and Temperature · NCERT: Class 7, Ch 2 "Understanding the Weather"; Class 11, Ch 4 "Climate"; Class 11, Ch 8 "Solar Radiation, Heat Balance and Temperature"; Class 11, Ch 11 "World Climate and Climate Change"
Meaning
The diurnal range of temperature is the day's highest temperature minus its lowest temperature. "Diurnal" means daily. The range is large where skies are clear and the air is dry. In such places the ground heats fast by day and loses heat fast at night. It is small over oceans, on coasts and in cloudy, humid places. There, water and clouds slow down both heating and cooling.
Example
The Thar Desert in western Rajasthan has a large diurnal range. Hot days are followed by much cooler nights under clear skies. Coastal Kerala, in south-west India, has a diurnal range of only about 7-8°C.
Don't confuse with
- Annual range of temperature: it compares the mean temperatures of the warmest and coldest months of the year, not the highest and lowest of a single day.