In meteorology, diurnal temperature variation is the variation between a high air temperature and a low temperature that occurs during the same day. Water is heated or cooled in a longer period of time than land. Because of this peculiar characteristic of water, the coastal areas enjoy a moderate climate and the difference in temperature of the warmest and coldest months is not very large. The desert regions have great diurnal temperature variation. On the contrary, low-lying humid areas have the least diurnal temperature variation. Diurnal range of temperature is the difference between the maximum and minimum temperatures of the same days. Cloud cover, urban heat, land-use change, aerosols, water vapor, and greenhouse gases are caused due to changes in the diurnal range of temperature. Over the last 50 years, negative trends in the Diurnal Temperature Range (DTR) have been observed due to an approximately 0.9°C increase in daily minimum and only 0.6°C increase daily maximum temperature. Therefore, while the climate warms, we have a reduction of the DTR. However unlike other latitudes, the equator receives vertical rays of sunshine throughout the year. These regions experience less seasonal variations. The equatorial regions experience equal day and night throughout the year. Equatorial region has a warm climate throughout the year.

Diurnal temperature range (DTR), the difference between the maximum and minimum temperatures within 1 day, is an important meteorological indicator associated with climate change. High desert regions typically have the greatest diurnal-temperature variations, while low-lying humid areas typically have the least. The smallest annual temperature range occurs in the equatorial tropical climate zone, where the changing angle of the Sun through the seasons has a proportionally smaller effect on the total amount of sunlight received.Diurnal range of temperature is the difference between the maximum and minimum temperatures of the same days. Part of India that experiences the highest diurnal range of temperature is Thar Desert. This is because it is filled with sand which gets heated up quickly during day and cooled up very quickly during nights. Water is heated or cooled in a longer period of time than land. Because of this peculiar characteristic of water, the coastal areas enjoy a moderate climate and the difference in temperature of the warmest and coldest months is not very large.