Temperature patterns follow the seasonal energy input from the sun - with the northern hemisphere warmer in the months June-August (northern summer) and colder in the months December-February (northern winter). The ocean has a higher heat capacity than the land - it heats up and cools down more slowly - so at a given latitude, the ocean is usually cooler than the land in summer and warmer in winter. This can be seen very clearly in January in the northeast Atlantic, where the Gulf Stream carries warm water from the tropics to the cold coasts of northern Europe. Such warm currents modify the local climate, making western Europe milder than other areas at the same latitude. In other areas, cold currents such as the Humboldt Current off western South America bring cold polar water back to the Equator.

The altitude of the land also modifies the temperature, since the air becomes less dense and therefore colder: the high Tibetan Plateau and the Andes Mountains are cooler than surrounding areas throughout the year.