Distribution of temperature varies both horizontally and vertically.
Distribution of temperature across the latitudes over the surface of the earth is called its horizontal distribution. On maps, the horizontal distribution of temperature is commonly shown by Isotherms, lines connecting points that have equal temperatures. The factors responsible for the uneven distribution of temperature are:
Horizontal Distribution of Temperature in January
In January, the sun shines vertically overhead near the Tropic of Capricorn. Hence it is summer in southern hemisphere and winter in northern hemisphere.
Horizontal Distribution of Temperature in July
During this period the sun shines vertically overhead near the Tropic of Cancer. Hence, high temperatures are found in the entire northern hemisphere.
The permanent snow on high mountains, even in the tropics, indicate the decrease of temperature with altitude. The average rate of temperature decrease upward in the troposphere is about 60°C per km, extending to the tropopause.